COLLEGE PHYSICS XII MULTIPLE CHOICE QUESTIONS

XII Physics MCQs, or XII Multiple Choice Questions, are a common assessment format used to evaluate a student’s understanding of physics concepts at the physics II level. These questions typically present a question or problem followed by four answer options, with only one being correct. They cover a wide range of topics within the XII Physics curriculum, including Molecular Theory of Gases, First Law of Thermodynamics, Second Law of Thermodynamics, Magnetic Fields, Electromagnetic induction, Alternating Current, Physics of Solids, Solid State of Electronics , Digital Electronics,  Relativity, Quantum Physics,  Atomic Physics, Particle Physics

The Molecular Theory of Gases (or Kinetic Theory of Gases) explains the behavior of gases based on the motion of their molecules. It provides a microscopic understanding of gas properties such as pressure, temperature, and volume.
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MOLECULAR THEORY OF GASES

MOLECULAR THEORY OF GASES

STD7

 

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1. The relationship between temperature and average kinetic energy of particles in a gas is

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2. Equal volumes of two gases at the same temperature and pressure have the same .

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3. The degree of freedom of a triatomic gas is?

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4. The kinetic energy per mole of a gas is:

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5. In air at S.T.P, the average speed of the:

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6. What is the shape of the graph that is drawn between pressure and volume?

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7. The Vrms of gas molecules is 300 m/sec. If its absolute temperature is reduced to half and the molecular weight is doubled, the Vrms will become:

75 m/sec                                                                              150 m/sec

300 m/sec                                                                           600 m/sec

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8. To hold Boyle’s law, the gas should be 

perfect and of constant mass and temperature
real and of constant and temperature
perfect and constant temperature but variable mass
real and constant temperature but variable mass

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9. Heat energy cannot be measured in:

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10. The speed of three particles is recorded as 3 m/s, 4 m/s, and 5 m/s. What is the root mean square speed of these particles?

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11. Calculate the root mean square speed of hydrogen in m/s at 27°C.

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12. A gas behaves as an ideal gas at ___________

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13. What is the average velocity of the molecules of an ideal gas?

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14. If the pressure of a gas contained in a closed vessel is increased by 0.5% when heated by 2ºC, then the initial temperature must be

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15. The normal human body temperature is:

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16.     Standard conditions of temperature and pressure (STP) refer to a gas at.

 

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17. Which among the following options do you think has the highest average speed?

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18.   If the absolute temperature of a gas is increased 3 times, the rms velocity of the molecules will be:

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19. The monoatomic molecules have only three degrees of freedom because they can possess

(a) only translatory motion

(b) only rotatory motion

(c) both translatory and rotatory motion

(d) translatory, rotatory and vibratory motion

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20. The density of carbon dioxide gas at 0ºC and at a pressure of 1.0 × 105 newton/metre2 is 1.98kg/m3. Find the root mean square velocity of its molecules at 0ºC. Pressure is constant.

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21. Which of the following parameters is the same for molecules of all gases at a given temperature?

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22. If the temperature is kept constant and the volume of a gas is doubled, the pressure of the gas is.

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23. The temperature of a gas is 100 K. It is heated until it reaches 200 K. Then, what do you understand regarding kinetic energy in this process?

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24. A certain perfect gas is found to obey PV3/2 = const during an adiabatic process. If such a gas at initial temperature T is adiabatically compressed to half the initial volume, the final temperature will be –

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25. In the Celsius scale, 1 °C in magnitude is equal to:

 

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26. The Fahrenheit and Celsius scales of temperature coincide at

 

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27. The Moon has no atmosphere because

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28. Avogadro’s number is the number of molecules in:

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29. 273 K is equal to

 

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30. The ratio of the rms velocities of O2 and H2 at equal temperature will be :

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A magnetic field is a fundamental physical phenomenon produced by moving electric charges, such as electric currents, or by intrinsic magnetic moments of elementary particles (like electrons). It exerts a force on other moving charges and magnetic materials within its influence

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MAGNETIC FIELD

MAGNETIC FIELD

Earth s magnetic field pillars

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1. A proton enters a magnetic  with a velocity of 5 × 107 ms-1 at an angle of 30o with the field. The force on the proton is 2 × 10-11 N. Find the magnetic field

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2. If the magnetic field is increased, the time period of revolution of a charged particle in a circular path will:
Hint { T = 2 π m/qB }

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3. A charged particle moves in a 0.5 T magnetic field with a time period of 2𝜋×10−7 . The particle is:

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4. Units of a magnetic field might be:

  1. C·m/s
  2. C·s/m
  3. C/kg
  4. kg/C·s
  5. N/C·m

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5. The cathode rays in J.J. Thomson’s experiment were accelerated using.

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6. In Thomson’s experiment, if the electric field E and magnetic field B are adjusted such that the beam is undeflected, the velocity v of electrons is given by:

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7. The magnetic field due to a long straight current-carrying conductor is independent of-

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8. A beam of electrons passes undeflected through crossed electric (1000 V/m) and magnetic (0.001 T) fields. The speed of the electrons is:

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9. The SI unit of the magnetic field is ____

 

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10. Which of the following will experience a maximum force, when projected with the same velocity perpendicular to the magnetic field : (i) α-particle, and (ii) β-particle?

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11. In J.J. Thomson’s experiment, what was the purpose of applying electric and magnetic fields to the cathode rays?

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12. J.J. Thomson’s experiment ultimately led to which major conclusion about the atom?

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13. A charged particle is projected into a region with both electric and magnetic fields perpendicular to each other. If the forces due to both fields balance each other, the particle will:

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14. Which of the following is true about the magnetic field produced by an infinite straight wire carrying a current?

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15. The discharge tube in Thomson’s experiment was evacuated to low pressure to:

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16. An electron moving with a velocity of 15 ms-1 enters a uniform magnetic field of 0.2 T, along a direction parallel to the field. What would be its trajectory in this field?

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17. There is a thin conducting wire carrying current  2A. The value of magnetic field induction at any point on the conductor would be:

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18. J.J. Thomson’s experiment ultimately led to which major conclusion about the atom?

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19. If the speed of a changed particle moving through a magnetic field is increased, then the radius of curvature of its trajectory will _____ .

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20. The work done by a magnetic field on a moving charged particle is:
a) Always positive
b) Always negative
c) Zero
d) Depends on the angle between V and B

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21. A long straight conductor carries a current of 5 A. The magnitude of the magnetic field at a point 20 cm from the conductor is:

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22. 10-4   Tesla equal to

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23. In Fleming’s left rule, the middle finger represents ________________.

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24. The Path of a charged particle entering perpendicular to the magnetic field will be _____ .

(a)          linear

(b)          circular

(c)           elliptical

(d)          parabolic

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25. Equal currents are passing through two very long and straight parallel wires in mutually opposite directions. They will _____ 

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26. J. Thomson’s experiment, involving the motion of an electron beam in mutually perpendicular E and B fields, gave the value of:

  1. mass of an electron
  2. charge of an electron
  3. Earth’s magnetic field
  4. charge/mass ratio for electrons

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Electromagnetic Induction is the phenomenon of generating an electromotive force (emf) or electric current in a conductor when it is exposed to a changing magnetic field. This principle, discovered by Michael Faraday in 1831, forms the basis for most modern electrical power generation systems.

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ELECTROMAGNETIC INDUCTION

ELECTROMAGNETIC INDUCTION

STD31

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1. A rod of length 1 m moves perpendicular to a magnetic field of 0.5 T at 4 m/s. The induced emf across its ends is:

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2.  Which among the following is true about Faraday’s law of Induction?

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3. If the conductor is stationary and the field is changing (varying), then an emf is induced in it. Such an emf is known as:

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4. In a circuit with a coil of resistance 2 Ω  , the magnetic flux changes from 2.0  Wb to 10.0  Wb in  0.2 s. The charge that flows in the coil during this time is:

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5. Current of 2 A passing through a coil of 100 turns gives rise to a magnetic flux of 5 × 10-5 Wb/turn, the magnetic energy associated with the coil is _____ J.

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6. A solenoid with 500 turns has a self-inductance of 5 H. If the current changes at 2 A/s, the induced emf is:

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7. Which of the following inductors will have the least eddy current losses?

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8. A coil of 200 turns has a flux change of 0.05 Wb/s. The induced emf is:

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9. The magnetic flux through a circuit of resistance  R  changes by an amount  Δ 𝜙  in time  Δ t. Then the total quantity of electric charge Q, which passes during this time through any point of the circuit, is given by:

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10. A coil of area 0.1 m² is placed in a magnetic field of 0.2 T. If the coil is rotated from 0° to 90° in 0.05 s, the average emf induced is:

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11. Mutual inductance of a system of two coils is 4 mH. In one coil, current changes with time according to I = sin (50πt). The induced emf in the other coil as a function of time is _____ V.

(a)          50π cos (50πt)

(b)          5π cos (50 πt)

(c)           π cos (50 πt)

(d)          π sin (50 πt)

Answer:

Option (c)

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12. The self-inductance of a coil is L. Keeping the length and area the same, the number of turns in the coil is increased to four times. The self-inductance of the coil will now be 

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13. To induce emf in a coil, the magnetic flux linked with a coil _____.

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14. Two circuits have a coefficient of mutual induction of 0.09 henry. Average e.m.f. induced in the secondary by a change of current from 0 to 20 amperes in 0.006 seconds in the primary will be 

1. 120 V

2. 80 V

3. 200 V

4. 300 V

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15. Unit of magnetic flux density is _____.

 

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16. Lenz’s law is a consequence of the law of conservation of 

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17. Which of the following is a unit of inductance?

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18. A coil having 500 square loops, each side 10 cm, is placed normal to a magnetic field which increases at the rate of 1.0 tesla/second. The induced e.m.f. in volts is 

  1. -0.1
  2. -0.5
  3. -1.0
  4. -5.0

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19. Faraday’s laws are result of the conservation of which quantity?

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20. A square loop of side 2 m is placed perpendicular to a uniform magnetic field of 0.5 T. If the field reduces to zero in 0.1 s, the induced emf is:

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21. Mutual inductance of a system of two coils is 0.3 H. If the current in the one coil is changed from 10 A to 40 A in 0.01 sec, the average induced emf in the other coil is _____ volt.

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22. A circular loop of radius 1 m is placed in a magnetic field of 0.2 T. If the field is reversed in 0.5 s, the induced emf is:

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23. If all linear dimensions of an inductor are tripled, then self-inductance will become (keeping the total number of turns per unit length constant)

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24. If a current of 10 A flows in one second through a coil, and the induced e.m.f. is 10 V, then the self-inductance of the coil is 

25 / 30

25. A copper ring is held horizontally, and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is-

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26. A coil and a bulb are connected in series with a DC source, and a soft iron core is then inserted in the coil. Then 

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27. A coil of 100 turns is wound on a magnetic circuit of reluctance 1000 AT/mWb. The current of 1A flowing in the coil is reversed in 10 ms. The average EMF induced in the coil is ________ V.

 

0.1 V

2 V

0.2 V

1 V

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28. A coil has 100 turns, and the magnetic flux through it changes from 0.02 Wb to 0.08 Wb in 0.2 seconds. The induced emf is:

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29. Which factor does NOT affect the magnitude of motional EMF in a conductor?

 

The speed of the conductor

The length of the conductor

The resistance of the conductor

The angle between the conductor’s velocity and the magnetic field

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30. A Coil of resistance 20 Ω   and inductance 5 H has been connected to a 200 V battery. The maximum energy stored in the coil is

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The First Law of Thermodynamics is a fundamental principle in physics and engineering that states the conservation of energy for thermodynamic systems. It establishes the relationship between heat, work, and internal energy.
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Created by 083d961d8a9401f1d6a2e30aa14eacc593376987fb08a9d53961f6fc44fe9de0?s=32&d=mm&r=gProf: ImranHashmi

FIRST LAW OF THERMODYNAMICS

FIRST LAW OF THERMODYNAMICS

Should Students Be Allowed to Redo Their Assignments

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1. In an experiment, some amount of water requires 12600 J of thermal energy to raise it from 30 °C to 60 °C, the heat capacity of water is

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2. A refrigerator rejects 400 J of heat while the compressor does 100 J of work. The heat extracted from the cold reservoir is:

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3. In a certain process, 400 J of heat is supplied to a system, and at the same time 150 J of work is done by the system. What is the increase in the internal energy of the system?

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4.  Boyle’s Law holds good for an ideal gas in a process called:

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5. The amount of energy required to change the liquid to gas and vice versa without any change in temperature is termed as

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6. If a gas absorbs 900 J of heat and does 500 J of work, what is the change in internal energy?

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7.   For a diatomic ideal gas Cv is

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8. For a polyatomic ideal gas Cv is

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9. Which of the following is an example of the First Law of Thermodynamics?

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10. A gas is heated at constant volume (ΔV = 0), absorbing 150 J. The work done is:

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11.   For a mono-atomic ideal gas Cv is

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12.    Enthalpy is directly proportional to…

 

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13.     What is the characteristic of an adiabatic process?

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14.  What is internal energy in a thermodynamic system?

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15. The heat capacity of a chemical is 750 J °C-1, and the mass is 15 kg. The heat capacity of the chemical would be

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16. What type of process occurs when a system exchanges both heat and work with its surroundings, and there is no change in internal energy?

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17. In a laboratory, a Bunsen burner is used to increase the temperature of lime from 10 °C to 50 °C with a thermal energy of 80000 J. If the mass of the lime is 20 kg, the specific heat capacity of the lime would be

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18. If ΔU = -60 J for a process where the system does 80 J of work, Q will be:

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19. An iron ball with a mass of 20 kg is raised from a temperature of 20 °C to 80 °C. If the thermal energy used by the iron ball is 598800 J, the specific heat capacity of the iron ball would be

 

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20.  The first law of thermodynamics is based on?

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21.  During an isobaric process, what remains constant?

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22. In which thermodynamic process does a system exchange heat with its surroundings but does not change temperature?

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23. If a cup of tea at 50 °C is allowed to cool to room temperature, the heat released would be (assume room temperature to be equal to 25 °C and heat capacity of the cup and tea to be = 5.0 kJ ⁄ K)

 

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24. Consider a gas contained in a rigid container of volume 20 m3. What will be the change in internal energy if 50 J of heat is provided to it? Assume the gas exerts a pressure of 1 atm        on the walls. 

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25. A gas absorbs 5000 J of heat and its volume increases at constant pressure (P = 2 KPa) from 1 m³ to 3 m³. The change in internal energy is:

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26. How is the change in internal energy (∆U) defined in terms of heat( ∆Q and work     (∆ W)

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27. A system loses 120 J of heat while 40 J of work is done on it. ΔU is:

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Both solenoid and toroid are electromagnets—devices that produce a magnetic field when an electric current passes through them. They are widely used in electrical and electronic applications due to their ability to generate controlled magnetic fields. They produce a strong, uniform magnetic field
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Created by 083d961d8a9401f1d6a2e30aa14eacc593376987fb08a9d53961f6fc44fe9de0?s=32&d=mm&r=gProf: ImranHashmi

SOLENOID AND TOROID

SOLENOID AND TOROID

Picture3

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1. The magnetic field intensity at a distance r from a long wire carrying current i is 0.4 tesla. The  magnetic field intensity at a distance 2r is.

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2. The field outside an ideal toroid is zero because:

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3. When an AC flows through a solenoid, the magnetic field inside:

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4. There are 100 turns per cm length in a very long solenoid. It carries a current of 5 A. The magnetic field at its centre on the axis is _____ T.

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5. The magnetic field at the centre of a current-carrying coil is B0 If its radius is reduced to half, keeping the current “same”, then the magnetic field at its centre becomes:

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6. The magnetic field inside a long solenoid is independent of:

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7. Find the true statement.

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8. The magnetic field at a point P situated at perpendicular distance ‘R’ from a long straight wire carrying a current of 12 A is 3 × 10-5 Wb/m2. The value of ‘R’ in mm is   [   μ0 = 4π × 10-7 Wb/Am  ]

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9. If a current flows through a toroidal coil, the magnetic field is:

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10. If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be _________

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11. A wire of length 0.5 m carries a current of 2 A. If the wire is placed in a uniform magnetic field of 4×10 −2 T perpendicular to the wire, what is the force on the wire?

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12. In an ideal toroid, the direction of the magnetic field at any point inside is:

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13. The magnetic field produced by a current-carrying solenoid at its center is 2×10 −2 T. If the current is 4 A and the solenoid has 200 turns, what is the length of the solenoid?

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14. The magnetic field inside a solenoid is 4 × 10 −3 T. If the solenoid has 1000 turns per meter, what is the current flowing through the solenoid?

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15. Solenoid with Iron Core When a soft iron core is inserted into a solenoid, the magnetic field inside:

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16. A very long solenoid of length L has n layers. There are N turns in each layer. Diameter of the solenoid is D and it carries current I. The magnetic field at the centre of the solenoid is _____ .

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17. The ampere circuital law is used to find.

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18. Which of the given properties can’t be calculated using the Biot-Savart equation?

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19. If the area of a solenoid’s cross-section is doubled while keeping the number of turns and current constant, the magnetic flux through it.

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20. A solenoid has n turns per meter and carries a current of 2 A. The magnetic field inside the solenoid is 4×10 −3 T. What is the number of turns per meter.

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21. If the current in a solenoid is doubled while the number of turns per unit length is kept constant, what happens to the magnetic field inside the solenoid?

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22. For a solenoid carrying a current, the magnetic field inside is:

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23. Which of the following configurations does not apply Ampère’s law directly to calculate the magnetic field?

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24. Two concentric rings are kept in the same plane. The number of turns in both rings is 20. Their radii are 40 cm and 80 cm, and they carry electric currents of 0.4 A and 0.6 A, respectively, in mutually opposite directions. The magnitude of the magnetic field produced at their centre is _____ T.

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25. Ampere’s circuital law involves finding the _________.

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An AC generator (or alternator) converts mechanical energy into alternating current (AC) electricity using electromagnetic induction. A transformer is a static device that changes AC voltage levels (steps up or down) using mutual induction between two coils
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Created by 083d961d8a9401f1d6a2e30aa14eacc593376987fb08a9d53961f6fc44fe9de0?s=32&d=mm&r=gProf: ImranHashmi

AC GENERATOR AND TRANSFORMER

AC GENERATOR AND TRANSFORMER

STD4

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1. The full-load copper loss of a transformer is 1600 W. At half-load, the copper loss will be _______

2 / 30

2. An AC generator produces an output voltage V=300 sin(100πt). The period of the AC cycle is:

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3. A 20 kVA auto-transformer steps down 500 V to 400 V. How much power is transferred conductively?

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4. An AC generator with a coil of 500 turns and area 0.1 m² rotates at 3000 rpm in a 0.5 T field. The peak emf is:

 (Take 𝜋 =3.14 )

  1. a) 785 V b) 1570 V c) 3140 V                    d) 4710 V

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5. The efficiency of a transformer is given by:

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6. For a 20kVA transformer with a turn ratio of 0.4, what amount of total power is transferred inductively?     

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7. In A.C. generator, increasing the no. of turns in the coil

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8. Which of the following is the main advantage of an auto-transformer over a two-winding transformer?

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9. The application of an electric motor is to

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10. In a step-down transformer, the number of turns in the secondary coil is 

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11. The AC generator is made up of a 50-turn coil with a 2.5m2 area rotating at 60 rad/s in a uniform magnetic field of 0.3 T between two fixed pole pieces. When the current is zero, what is the flux across the coil?

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12. Which of the following is a unit of inductance?

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13. In a transformer, eddy current loss is reduced by

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14. The shape of the output voltage waveform of an AC generator is:

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15. According to Lenz’s law, what does the secondary current in a transformer produce?

 

 A magnetizing effect

An EMF to oppose the primary voltage

A back EMF that resists the load

A demagnetizing effect

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16. For a 20kVA transformer with a turn ratio of 0.4, what amount of total power is transferred inductively?  

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17. The efficiency of a transformer is maximum when:

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18. A generator has 50 turns and rotates at 60 Hz in a 0.4 T magnetic field. If the peak emf is 150 V, the area of the coil is:

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19. What is the thickness of laminations used in a transformer?

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20. Which loss occurs in the core of a transformer due to alternating magnetic flux?

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21. A 25 kVA transformer has 500 primary turns and 50 secondary turns. If the primary is connected to 1000 V, what is the secondary current at full load?

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22. The basic difference between an AC generator and a DC generator is that

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23. A generator coil with 200 turns rotates at 1500 rpm in a 0.2 T magnetic field. If the coil area is 0.05 m², the peak emf is:

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24. To convert an AC generator to a DC generator, what replacement is required?

25 / 30

25. What is the working principle of an AC generator?

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26. A transformer has 100 primary turns and 200 secondary turns. If the input voltage is 50 V AC, the output voltage is:

27 / 30

27. Which of the following inductors will have the least eddy current losses?

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28. If the speed of rotation of an AC generator is doubled, the induced emf will:

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29. In a transformer, the primary and secondary coils are wound around:

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30. An a.c. The generator is composed of a 100-turn coil with a 3 m² cross-sectional area that rotates at 60 rad/s in a uniform magnetic field of 0.04 T. The coil has a resistance of 500. Calculate the generator’s maximum current draw.

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The Second Law of Thermodynamics is a fundamental principle that governs the direction of natural processes, emphasizing irreversibility and the concept of entropy. it explains that Natural processes are irreversible

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Created by 083d961d8a9401f1d6a2e30aa14eacc593376987fb08a9d53961f6fc44fe9de0?s=32&d=mm&r=gProf: ImranHashmi

SECOND LAW OF THERMODYNAMICS

SECOND LAW OF THERMODYNAMICS

STD

 

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1. A refrigerator has a performance coefficient of 5. Calculate the ambient heat discharged if the temperature inside the freezer is -20 oC

2 / 27

2. A heat engine rejects 300 J to a cold reservoir at 250 K and has an efficiency of 30%. What is the heat absorbed from the hot reservoir?
(a) 428.57 J
(b) 500 J
(c) 1000 J
(d) 700 J

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3. A frictionless heat engine can be 100% efficient only if its exhaust temperature is:

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4. The Kelvin-Clausius statement of the Second Law says:

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5. A Carnot engine has an efficiency of 40%. If the cold reservoir is at 27°C, what is the temperature of the hot reservoir?

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6. The efficiency of diesel engines is

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7. The area of a Carnot cycle graph represents

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8. Which device is not used in a diesel engine

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9. The practical efficiency of diesel engines is about

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10. The correct sequence of the processes taking place in a Carnot cycle is…….

(a)  adiabatic- adiabatic- isothermal- isothermal

(b) adiabatic- isothermal- adiabatic_ isothermal

(c) isothermal-isothermal adiabatic -adiabatic

(d) isothermal -adiabatic isothermal-adiabatic

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11. A refrigerator, with its door open. The temperature of the room will

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12. The Second Law of Thermodynamics implies that:

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13. The change in entropy is given by

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14. A refrigerator has a coefficient of performance (COP)  of 4. How much work is needed to remove 200 J of heat from the cold reservoir?

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15. The net change in entropy of a system in a natural process is

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16. A system that exchanges mass and energy with its surroundings is called……..

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17. The refrigerator and heat pump work on which principle?

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18. The change in entropy is negative when:

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19. If the entropy of a system increases by 50 J/K while the temperature remains at 300 K, how much heat is transferred?

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20. The process violates the 2nd law of thermodynamics:

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21. Otto cycle is perfectly………

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22. A reversible engine takes 1000 J from a 600 K reservoir and rejects heat to a 300 K reservoir. How much work is done per cycle?

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23. Which one of the following processes is irreversible?

(a) Slow compression of an elastic spring

(b) Slow evaporation of a substance in an isolated vessel

(c) Slow compression of a gas

(d) A chemical explosion

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24. A system absorbs 500 J of heat at 350 K. What is the change in entropy of the system?

(a) 1.43 J/K (b) 0.7 J/K (c) 2.5 J/K (d) 0.5 J/K

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25. A refrigerator violates the Second Law if:

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26. A Carnot engine operates between 800 K and 480 K. What is its efficiency?

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27. The change in entropy is negative when:

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A galvanometer is an electromechanical instrument used to detect and measure small electric currents by converting electrical energy into mechanical motion. It is susceptible and forms the ammeters and voltmeters.
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Created by 083d961d8a9401f1d6a2e30aa14eacc593376987fb08a9d53961f6fc44fe9de0?s=32&d=mm&r=gProf: ImranHashmi

GALVANOMETER AMMETER VOLTMETER

GALVANOMETER AMMETER VOLTMETER

testi img2

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1. A galvanometer has a resistance of 50 ohms, and it deflects full scale when a current of 10 milliamperes flows in it. How can it be converted into an ammeter of range 10 A?

5  Ω                       0.5  Ω                   0.05  Ω                 0.005  Ω        Ans      0.05  Ω

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2. The sensitivity of a galvanometer is given by

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3. Phosphor-bronze wire is used in suspension because it has:

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4. The coil of a galvanometer, which has a resistance of 50 ohms and a current of  50 microamperes, produces full-scale deflection in it. Show by a diagram how it can be converted to a voltmeter of a 300-volt range, and compute the series resistance.

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5. The working principle of a moving coil galvanometer is based on:

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6. A Galvanometer connected with high resistance in series is used as _____.

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7. In ballistic galvanometer, the frame on which the coil is wound is non-metallic. It is

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8. What happens when the shunt resistance of a galvanometer circuit is increased? 

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9. In a galvanometer, 15% of the total current in the circuit passes through it. If the resistance of the galvanometer is G, then find out the shunt resistance S that is connected to the galvanometer.

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10. In a multi-range ammeter, as the range increases

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11. The deflection in a moving coil galvanometer is

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12. In a moving coil galvanometer, the restoring torque is provided by:

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13. What is the shape of a magnet in a moving coil galvanometer to make the radial magnetic field?

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14. Which one of the following is not an electromechanical instrument?

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15. A galvanometer whose resistance is 40 ohms deflects full-scale for a potential difference of 100 millivolts across its terminals. How can it be converted into an ammeter with a 5-ampere range?

2 Ω                              0.2 Ω                           0.02 Ω                                0.002 Ω

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16. How is a galvanometer converted into an ammeter?

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17. A galvanometer has resistance of 10 ohms and a full scale deflection is produced by 5 milli amperes. What is the value of resistance that should be connected in series with it in order to enable it to read 2V?

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18. A sensitive galvanometer gives full-scale deflection with 100 mV. If the resistance of the galvanometer is 50 Ω ? the maximum current that can flow through safely is:

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19. How is galvanometer converted into a voltmeter?

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20. The deflection θ is related to the electric current I in a galvanometer by the relation

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An Alternating Current (AC) circuit is an electrical circuit powered by a voltage or current that periodically reverses direction, unlike a Direct Current (DC), which flows in one direction. AC circuits are fundamental to power distribution, electronics, and communication systems due to their transmission efficiency
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Created by 083d961d8a9401f1d6a2e30aa14eacc593376987fb08a9d53961f6fc44fe9de0?s=32&d=mm&r=gProf: ImranHashmi

AC CIRCUIT

AC CIRCUIT

STD34

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1. The phase angle between the voltage and the current in an AC circuit consisting of a resistance is______________?  

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2. The Power factor of an electrical circuit is equal to

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3. In Alternating Current (AC), the direction and magnitude of the current varies

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4. The magnetic energy stored in an inductor of inductance    4   𝜇 H carrying a current of    2   A is :

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5. An ac source is connected in the given circuit. The value of Φ will be

Picture6

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6. An A.C. source is connected to a capacitor. Due to a decrease in its operating frequency;

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7. The average power supplied to an inductor over one complete alternating current cycle is _________.

 

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8. The maximum power is dissipated for an ac in a/an:

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9. A 10 𝜇 F capacitor is connected to a 210V ,  50 Hz source . The peak current in the circuit is nearly ( 𝜋 = 3.14 ) :

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10. The ‘time constant’ of a series RC circuit is

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11. The r.m.s. The value of alternating current is given by the steady (D.C.) current, which, when flowing through a given circuit for a given time, produces

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12. Average power in LCR circuit depends upon

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13. In the case of the A.C. circuit, Ohm’s law holds good for;

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14. The self-inductance of a choke coil is 10 mH. When it is connected to a 10-volt D.C. source, then the loss of power is 20 watts. When it is connected to 10 volt A.C. source loss of power is 10 watts. The frequency of A.C. source will be;

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15. If a capacitor is connected to two different A.C. generators, then the value of capacitive reactance is;

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16. When an A.C. source is connected across a resistor;

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17. The reactance of capacitor at 50 Hz is 5Ω. If the frequency is increased to 100 Hz, the new reactance is

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18. A 40 µF capacitor is connected to a 200 V, 50 Hz ac supply. The rms value of the current in the circuit is, nearly :

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19. Statement-I: The Capacitor serves as a block for D.C. and offers an easy path to A.C.  Statement II: Capacitive reactance is inversely proportional to frequency.

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20. The ratio of the RMS value divided by the average value is known as ____________ factor

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21. The average power dissipated in one cycle is :

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22. An inductor of reactance 1 Ω and a resistor of 2 Ω are connected in series to the terminals of a 6 V (rms) a.c. source. The power dissipated in the circuit is

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23. The frequency of an alternating current is 50 Hz. In how much time does it reverse its direction?

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24. A pure capacitor of capacitance 100μF is connected to an A.C. voltage, V = 100sin (10t). Find the maximum current in the circuit.

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25. The peak value of an A.C. is 2√2 A, its rms value will be:

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26. Value of current in an A.C. circuit is I = 2cos(ωt + θ). The value of Irms is:

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27. In any A.C. circuit, always

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28. An AC source is connected to a capacitor C. Due to a decrease in its operating frequency

A displacement current increases.      B displacement current decreases.

C capacitive reactance remains constant.       D capacitive reactance decreases.

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29. An inductor may store energy in ________________?

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30. In a series LCR circuit, the inductance 𝐿 is 10 mH , the capacitance 𝐶 is    1𝜇 F and the resistance 𝑅 is  100 Ω. The frequency at which resonance occurs is:-

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