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

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

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

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

 

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

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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. The normal human body temperature is:

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

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

 

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13. 273 K is equal to

 

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14. A gas behaves as an ideal gas at ___________

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

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16. 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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17. The kinetic energy per mole of a gas is:

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18. The Moon has no atmosphere because

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19. 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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20. The Fahrenheit and Celsius scales of temperature coincide at

 

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

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22. 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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23. Heat energy cannot be measured in:

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

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25. 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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26. 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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27. Equal volumes of two gases at the same temperature and pressure have the same .

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

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

Your score is

The average score is 24%

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

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

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

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7. 10-4   Tesla equal to

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

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10. 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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11. 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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12. 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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13. 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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14. 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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15. 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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16. 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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17. Which of the following is true about the magnetic field produced by an infinite straight wire carrying a current?

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

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

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21. The SI unit of the magnetic field is ____

 

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

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23. 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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24. 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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25. In J.J. Thomson’s experiment, what was the purpose of applying electric and magnetic fields to the cathode rays?

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

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

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5. 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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6. 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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7. 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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8. Lenz’s law is a consequence of the law of conservation of 

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9. 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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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. 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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12. 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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13. 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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14. 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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15. Unit of magnetic flux density is _____.

 

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

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17. 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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18. 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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19. 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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20. 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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21. 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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22. 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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23.  Which among the following is true about Faraday’s law of Induction?

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

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27. 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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28. 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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29. 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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30. Faraday’s laws are result of the conservation of which quantity?

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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.    Enthalpy is directly proportional to…

 

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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.   For a diatomic ideal gas Cv is

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4.     What is the characteristic of an adiabatic process?

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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. 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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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.  What is internal energy in a thermodynamic system?

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9. 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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10. 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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11. 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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12. How is the change in internal energy (∆U) defined in terms of heat( ∆Q and work     (∆ W)

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13. 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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14. 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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15. Which of the following is an example of the First Law of Thermodynamics?

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16. 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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17.  During an isobaric process, what remains constant?

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18.  The first law of thermodynamics is based on?

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

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

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22.   For a mono-atomic ideal gas Cv is

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23. For a polyatomic ideal gas Cv is

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

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

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

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. Ampere’s circuital law involves finding the _________.

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

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

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

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

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7. 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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8. 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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9. 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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10. Solenoid with Iron Core When a soft iron core is inserted into a solenoid, the magnetic field inside:

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

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

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15. 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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16. 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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17. If a long hollow copper pipe carries a direct current, the magnetic field associated with the current will be _________

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18. Find the true statement.

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19. 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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20. 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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21. 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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22. The ampere circuital law is used to find.

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

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

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25. 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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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. The efficiency of a transformer is given by:

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

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

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5. 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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6. 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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7. An AC generator produces an output voltage V=300 sin(100πt). The period of the AC cycle is:

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

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9. The efficiency of a transformer is maximum when:

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

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

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

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

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

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

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

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

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

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

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

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

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24. The application of an electric motor is to

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

26 / 30

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

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27. 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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28. What is the working principle of an AC generator?

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29. 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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30. 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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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

 

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1. The change in entropy is negative when:

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2. The area of a Carnot cycle graph represents

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3. 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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4. Otto cycle is perfectly………

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5. The change in entropy is given by

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

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

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

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9. The practical efficiency of diesel engines is about

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

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11. 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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12. The Second Law of Thermodynamics implies that:

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13. 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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14. The process violates the 2nd law of thermodynamics:

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15. 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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16. 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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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. 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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20. The net change in entropy of a system in a natural process is

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21. 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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22. 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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23. 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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24. Which device is not used in a diesel engine

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25. The efficiency of diesel engines is

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26. A refrigerator violates the Second Law if:

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

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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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GALVANOMETER AMMETER VOLTMETER

GALVANOMETER AMMETER VOLTMETER

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

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2. 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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3. 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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4. 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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5. The deflection in a moving coil galvanometer is

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

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8. How is a galvanometer converted into an ammeter?

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

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

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

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

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

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

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16. The sensitivity of a galvanometer is given by

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

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18. How is galvanometer converted into a voltmeter?

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

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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 may store energy in ________________?

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

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

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

 

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7. Average power in LCR circuit depends upon

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

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

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

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

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

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16. The average power dissipated in one cycle is :

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17. 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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18. 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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19. The ‘time constant’ of a series RC circuit is

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20. In any A.C. circuit, always

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

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

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

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

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

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

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

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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. 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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