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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Created by Prof: ImranHashmi

MOLECULAR THEORY OF GASES

MOLECULAR THEORY OF GASES

 

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

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

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3. The Moon has no atmosphere because

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

 

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

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

 

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

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

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10. Heat energy cannot be measured in:

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11. 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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12. 273 K is equal to

 

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

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14. The Fahrenheit and Celsius scales of temperature coincide at

 

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

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17. 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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18. 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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19. Avogadro’s number is the number of molecules in:

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20. The normal human body temperature is:

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

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22. 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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23. 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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24. Equal volumes of two gases at the same temperature and pressure have the same .

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25. A gas behaves as an ideal gas at ___________

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

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27. 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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28. The kinetic energy per mole of a gas is:

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

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

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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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Created by Prof: ImranHashmi

MAGNETIC FIELD

MAGNETIC FIELD

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1. 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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2. 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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3. The magnetic field due to a long straight current-carrying conductor is independent of-

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4. 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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5. 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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6. 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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7. 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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8. The discharge tube in Thomson’s experiment was evacuated to low pressure to:

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

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10. 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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11. 10-4   Tesla equal to

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

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

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

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

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

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20. 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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21. 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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22. The cathode rays in J.J. Thomson’s experiment were accelerated using.

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23. 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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24. 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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25. The SI unit of the magnetic field is ____

 

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26. 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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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

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1. 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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2. 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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3. 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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4. 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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5. 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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6. 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 

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7. 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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8. Which of the following is a unit of inductance?

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9. 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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10. 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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11. 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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12. 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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13.  Which among the following is true about Faraday’s law of Induction?

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14. 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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15. 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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16. 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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17. Which of the following inductors will have the least eddy current losses?

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18. 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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19. 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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20. 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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21. To induce emf in a coil, the magnetic flux linked with a coil _____.

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22. 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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23. 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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24. Unit of magnetic flux density is _____.

 

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

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26. 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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27. 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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28. Faraday’s laws are result of the conservation of which quantity?

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

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30. 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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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 Prof: ImranHashmi

FIRST LAW OF THERMODYNAMICS

FIRST LAW OF THERMODYNAMICS

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1.  The first law of thermodynamics is based on?

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2.  What is internal energy in a thermodynamic system?

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

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5. 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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6. 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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7. 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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8.  Boyle’s Law holds good for an ideal gas in a process called:

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

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11. 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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12. 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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13. In which thermodynamic process does a system exchange heat with its surroundings but does not change temperature?

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14. 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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15. 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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16.   For a mono-atomic ideal gas Cv is

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17.  During an isobaric process, what remains constant?

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

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20. 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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21. 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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22.     What is the characteristic of an adiabatic process?

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

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

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25. For a polyatomic ideal gas Cv is

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26.   For a diatomic ideal gas Cv is

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27.    Enthalpy is directly proportional to…

 

Your score 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 Prof: ImranHashmi

SOLENOID AND TOROID

SOLENOID AND TOROID

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

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

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3. 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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4. 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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5. The magnetic field inside a long solenoid is independent of:

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6. 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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7. 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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8. When an AC flows through a solenoid, the magnetic field inside:

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

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

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

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

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16. The ampere circuital law is used to find.

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17. 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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18. Find the true statement.

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19. 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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20. 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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21. Ampere’s circuital law involves finding the _________.

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

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

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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 Prof: ImranHashmi

AC GENERATOR AND TRANSFORMER

AC GENERATOR AND TRANSFORMER

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

2 / 30

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

3 / 30

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

4 / 30

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

5 / 30

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

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6. 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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7. 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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8. 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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9. 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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10. The efficiency of a transformer is maximum when:

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

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

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

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

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

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

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

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

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

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22. The efficiency of a transformer is given by:

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

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

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

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

28 / 30

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

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

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30. The application of an electric motor is to

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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 Prof: ImranHashmi

SECOND LAW OF THERMODYNAMICS

SECOND LAW OF THERMODYNAMICS

 

1 / 27

1. The efficiency of diesel engines is

2 / 27

2. 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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3. Otto cycle is perfectly………

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4. 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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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 net change in entropy of a system in a natural process is

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7. 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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8. The process violates the 2nd law of thermodynamics:

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9. The practical efficiency of diesel engines is about

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10. The area of a Carnot cycle graph represents

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

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

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13. 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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14. The refrigerator and heat pump work on which principle?

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15. 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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16. The change in entropy is given by

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

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18. The Second Law of Thermodynamics implies that:

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

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20. A refrigerator violates the Second Law if:

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

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22. The change in entropy is negative when:

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

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24. 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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25. Which device is not used in a diesel engine

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26. The change in entropy is negative when:

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27. 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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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 Prof: ImranHashmi

GALVANOMETER AMMETER VOLTMETER

GALVANOMETER AMMETER VOLTMETER

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

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2. How is galvanometer converted into a voltmeter?

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3. 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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4. The sensitivity of a galvanometer is given by

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

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

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

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

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9. 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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10. 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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11. In a multi-range ammeter, as the range increases

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

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13. 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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14. 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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15. The working principle of a moving coil galvanometer is based on:

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

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

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19. The deflection in a moving coil galvanometer is

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20. How is a galvanometer converted into an ammeter?

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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 Prof: ImranHashmi

AC CIRCUIT

AC CIRCUIT

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1. 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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2. 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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3. The frequency of an alternating current is 50 Hz. In how much time does it reverse its direction?

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

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

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7. Average power in LCR circuit depends upon

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

 

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

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

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

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

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14. 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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15. The Power factor of an electrical circuit is equal to

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

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

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

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19. 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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20. The average power dissipated in one cycle is :

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21. In any A.C. circuit, always

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

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23. 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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24. 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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25. In the case of the A.C. circuit, Ohm’s law holds good for;

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26. 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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27. An inductor may store energy in ________________?

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

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

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