Quiz: Chapter 10 - Magnetism

1 The units of magnetic field B, in system international is:

Weber Tesla Gauss Newton

2 One tesla (T) is:

1T = 1N A m⁻¹ 1T = 1N A⁻¹ m⁻¹ 1T = 1N A m 1T = 1N m A⁻¹

3 The magnetic flux “Ø” through an area “A” is:

Ø = B × A Ø = B·A Ø = A × B None of these

4 One Tesla is also equal to:

Wb·m² Wb/m² Wb/m None

5 Torque on a current carrying coil is:

BINA cosα BINA sinα BIL cosα BIL sinα

6 The magnetic force is simply a:

Reflecting force Deflecting force Restoring force Gravitational force

7 The galvanometer can be made sensitive if the value of the factor C/BNA is:

Made large Made small Remains constant Infinite

8 When a small resistance is connected parallel to the galvanometer, the resulting circuit behaves as:

Voltmeter Wheatstone bridge Ammeter Potentiometer

9 The anode in the CRO is:

Controls number of electrons Controls brightness of spot Accelerates and focuses the beam At negative potential

10 The galvanometer constant in a moving coil galvanometer is given by:

K = NB/CA K = C/NAB K = C/NAB K = CA/NB

11 ∑ B·ΔL = μ₀I is the relation for:

Millikan’s law Gauss’s law Ampere’s law Lenz’s law

12 The brightness of spot on CRO screen is controlled by:

Anodes Cathodes Grid Plates

13 To measure current in a circuit, ammeter is always connected in:

Parallel Series Sometimes parallel Neither

14 If the angle between v and B is zero, then magnetic force will be:

Max Min Zero None

15 A charged particle is projected into a uniform magnetic field. Which parameter is affected?

Energy Momentum Speed Velocity

16 Force on a moving charge is maximum when angle between v and B is:

0° 30° 60° 90°

17 The S.I. unit of magnetic flux is:

Tesla Weber Joule Newton

18 Beam of electrons is also called:

Positive rays X-rays Cathode rays Cosmic rays

19 Tesla is the unit of:

Electric field Magnetic field Magnetic intensity Electric intensity

20 Can a magnetic field set a charge at rest into motion?

Yes No Sometimes None

21 The grid in CRO:

Controls electron count Controls brightness Both a and b Deflects beam

22 To convert a galvanometer into a voltmeter, series resistance is:

Rh = V/Ig Rh = (Ig - Rg)/Ig Rh = (Ig - Ig)/Rg None

23 Magnetic field around a straight current-carrying wire is:

Radial Square Varies with current Circular

24 Electron in magnetic field: r ∝ ?

m B 1/v 1/m

25 Torque in a coil can be increased by:

More turns Current & B Area of coil All of above

26 A current-carrying loop in a uniform B-field experiences:

Electric flux Torque Magnetic flux Force

27 Magnetic flux is maximum when angle between B and A is:

0° 60° 90° 180°

28 One weber is equal to:

N·A²/A N·m²/A N·A/m N·m/A

29 Waveform of sinusoidal voltage is found by:

CRO Diode Transistor Radio

30 Force on a charge moving parallel to B is:

Maximum Minimum Zero None

31 The induced e.m.f. is produced due to:

Motion of coil Motion of magnet Rate of change of flux None

32 Lenz’s law is about:

Conservation of momentum Conservation of energy Opposing change in flux Both b and c

33 Back e.m.f in a motor is maximum when:

Motor at max speed Motor at rest Cannot tell None

34 Application of mutual induction is:

Television Radio DC motor Transformer

35 Self-inductance is defined by:

L = -ε/(ΔI/Δt) L = -(ΔI/Δt)/ε L = -ε/(ΔØ/Δt) L = ε/(ΔØ/Δt)

36 AC generators lack:

Armature Magnet Slip rings Commutator

37 Energy stored in an inductor is:

½LI² ½LI ½L²I² ½LI

38 Lenz’s law aligns with conservation of:

Mass Energy Charge None

39 Inductor stores energy in:

Magnetic field Electric flux Electric field None

40 Negative sign in induced emf is due to:

Faraday’s law Lenz’s law Ampere’s law None

41 Motional emf when conductor moves ⊥ to B-field:

E = BLV E = qBl E = Blq E = qVB

42 Increasing circuit resistance affects induced emf:

Increases Decreases Remains same None

43 Unit of inductance is:

Coulomb Ampere Volt Henry

44 Overloaded motor draws:

Max current Min current Half current None

45 Coefficient of mutual inductance is:

ε(ΔIp/Δt) ε(Δt/ΔIp) εΔIpΔt None

46 AC changes:

Magnitude & direction Direction only Magnitude only None

47 Instantaneous AC voltage is:

V = Vo sin(2πft) V = Vo sin(2ft) V = Vo sin(2πwt) None

48 Induced emf in AC generator:

VBL sinϕ NESN sinϕ NAB sinϕ NIAB sinϕ

49 Back motor effect exists in:

Generator Motor AC meter None

50 Coil in generators is called:

Commutator Slip rings Armature None

51 Transformer principle is based on:

Ampere’s law Mutual induction Motional emf None

52 Ideal transformer steps up/down:

Energy Power Voltage All

53 Input coil of transformer is called:

Primary Secondary Middle None

54 Actual transformer output is:

Equal to input Less than input More than input None

55 For good transformer, hysteresis loops are:

Small Large Zero None

56 To minimize heating in transmission lines:

High current, low voltage High voltage, low current Same V & I None

57 Max emf in generator is:

ε = ε₀ sinθ ε = NωAB sinθ ε = NωAB None

58 Induced emf is:

∝ ΔΦ ∝ ΔΦ/Δt ∝ 1/ΔΦ None

59 1 henry equals:

1 V A s⁻¹ 1 V s A⁻¹ 1 V m A⁻¹ 1 V A m⁻¹

60 Device converting electrical to mechanical energy:

Transformer AC generator DC motor DC generator

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Chapter 10: Magnetism