chapter 3 MCQs 12th Class Physics

Electromagnetism:

1. The e/m of a neutron is:

a. Greater than election
b. Less than electron
c. The same as electron
d. Zero

d. Zero

2. An electron enters the magnetic field at right angle from left, is into paper. The electron will be deflected:

a. Downward
b. Upward
c. Toward left
d. Toward right

a. Downward

3. A current flowing towards the reader is denoted by:

a. A dot
b. Cross
c. Positive sign
d. A bracket

a. A dot

4. A current carrying conductor experiences maximum magnetic force in a uniform magnetic field when it is placed:

a. At an angle of 60^o to field
b. Perpendicular to field
c. At an angle of 180^o to field
d. Parallel to field

b. Perpendicular to field

5. Torque on a current carrying coil is given by:

a. IBA cos ∞
b. ILB cos ∞
c. IBA sin ∞
d. ILB sin ∞

a. IBA cos ∞

6. Torque is produced in a current carrying coil when it is placed in a:

a. Gravitational field
b. Magnetic field
c. Nuclear field
d. Electric field

b. Magnetic field

7. The SI unit of magnetic induction Tesla is equal to:

a. NA^-1 m
b. NA^-1 m^-1
c. NA² m^-1
d. NAm^-1

b. NA^-1 m^-1

8. The SI unit of magnetic permeability is:

a. WbmA^-1
b. WbA^-1m^-1
c. WbAm^-1
d. Wbm^-2

a. WbmA^-1

9. Magnetic induction can be measured in units of:

a. Weber / m²
b. Tesla
c. Gauss
d. All of above

d. All of above

10. The magnetic flux Φσ is equal to:

a. B/A
b. ^→B. ^→A
c. BA sin Φ
d. ^→B x ^→A

b. ^→B. ^→A

11. Magnetic flux density at a point due to current carrying coil is determined by:

a. Faraday’s Law
b. Ampere’s Law
c. Lenz’s Law
d. Gauss’s Law

b. Ampere’s Law

12. In current carrying long solenoid the magnetic field produced does not depend upon:

a. Current flowing through solenoid
b. The radius of solenoid
c. Number of turns per unit length
d. All of above

b. The radius of solenoid

13. Force on a charged particle is zero when projected at angle with magnetic field:

a. 180^o
b. 0^o
c. 270^o
d. 90^o

b. 0^o

14. The charges moving perpendicular to magnetic field experience force:

a. Zero
b. Maximum
c. Infinite
d. Minimum

b. Maximum

15. A voltmeter is always connected in:

a. Perpendicular
b. Parallel
c. Straight line
d. Series

b. Parallel

16. Force on a moving charge in a magnetic field is given by:

a. F = q (^→B + ^→v)
b. F = q (^→B x ^→v)
c. F = q (^→B – ^→v)
d. F = q (^→v x ^→B)

d. F = q (^→v x ^→B)

17. The sum of electric and magnetic force is called:

a. Newton’s force
b. Maxwell force
c. Centripetal force
d. Lorentz force

d. Lorentz force

18. One weber is equal to:

a. Nm^-1 A^-1
b. NmA^-1
c. Nm^-1 A^-2
d. Nm^-1 A

b. NmA^-1

19. Very weak magnetic field produced by brain can be detected by:

a. Squids
b. Compass
c. Liquids
d. Metallic needle

a. Squids

20. If F₁ and F₂ are the magnetic force acting on a particle and electron respectively, when moving perpendicular to the magnetic field than:

a. F1<F2
b. F1=F2
c. F1=4F2
d. F1>F2

a. F1<F2

21. A current carrying conductor is placed in uniform magnetic field parallel to it. The magnetic force experienced by the conductor is:

a. F=ILB cosΦ
b. F=ILB
c. F is zero
d. F=ILB sinΦ

c. F is zero

22. Two parallel wires carrying currents in the same direction:

a. Have no field around them
b. Have no effect
c. Attract each other
d. Repel each other

c. Attract each other

23. The force on current earning conductor placed in magnetic field is expressed by:

a. ^→F = l² ^→L X ^→B
b. ^→F = ^→ l L . ^→B
c. ^→F = ^→l B X ^→L
d. ^→F = ^→ l L X ^→B

d. ^→F = ^→ l L X ^→B

24. A 100 W bulb is switched on for half an hour. Heat lost due to flow of current is:

a. 3 KJ
b. 0.36 MJ
c. 0.18 MJ
d. 18 MJ4

c. 0.18 MJ

25. If current flowing through a solenoid becomes four times, then magnetic field inside it becomes:

a. Four times
b. Two times
c. Half
d. Three times

a. Four times

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12th class (Fsc) Physics unit 3 MCQs