Electromagnetic Induction — DPP 1

20 NEET questions from Electromagnetic Induction, with answers and explanations. Attempt it as a timed test to get scoring, accuracy breakdown and mistake tracking.

Attempt this test free 20 questions · 30 minutes · +80 marks
1
According to Faraday's Laws of electromagnetic induction:
  1. A The direction of the induced current is such that it opposes itself
  2. B The induced emf in the coil is proportional to the rate of change of magnetic flux associated with it
  3. C The direction of induced emf is such that it opposes itself
  4. D None of the above
Show answer

Correct answer: B

2
The magnetic flux in a coil of 100 turns increases by $12 \times 10 ^ { 3 }$ Maxwell in 0.2 s due to the motion of a magnet. The emf induced in the coil will be:-
  1. A 0.6 mV
  2. B 0.6 V
  3. C 6 V
  4. D 60 V
Show answer & explanation

Correct answer: A

$\begin{aligned} \varepsilon & =\frac{\Delta \phi}{\Delta \mathrm{t}}\left(1 \mathrm{~Wb}=10^{8} \text { Maxwell }\right) \\ & =\frac{12 \times 10^{+3} \times 10^{-8}}{0.2}=0.6 \mathrm{mV}\end{aligned}$
3
A square coil of $0.01 \mathrm {~m} ^ { 2 }$ area is placed perpendicular to the uniform magnetic field of $10 ^ { 3 }$ weber $/ \mathrm { m } ^ { 2 }$. The magnetic flux linked with the coil is :-
  1. A 10 weber
  2. B $10 ^ { - 5 }$ weber
  3. C Zero
  4. D 100 weber
Show answer & explanation

Correct answer: A

$\phi=\mathrm{BA} \cos 0^{\circ}=\mathrm{BA}=0.01 \times 10^{3}=10 \mathrm{~Wb}$
4
An emf is induced in a coil. The linking magnetic flux
  1. A Must be decreasing
  2. B Must be increasing
  3. C Must remain constant
  4. D Can be either increasing or decreasing
Show answer

Correct answer: D

5
A circular loop of radius r is moved away from a current carrying wire then induced current in circular loop will be :-
Electromagnetic Induction – NEET-20189
  1. A Clock wise
  2. B Anti clockwise
  3. C Not induced
  4. D None of them
Show answer

Correct answer: A

6
A charge particle moves along the line AB, which lies in the same plane of a circular loop of conducting wire as shown in the fig. Then :-
Electromagnetic Induction – NEET-20185
  1. A No current will be induced in the loop
  2. B The current induced in the loop will change its direction as the charged particle passes by
  3. C The current induced will be anticlockwise
  4. D The current induced, will be clockwise
Show answer

Correct answer: B

7
An aluminium ring B faces an electromagnet A. The current I through A can be altered. Then which of the following statements is correct :-
Electromagnetic Induction – NEET-20184
  1. A If I decreases A will repel B
  2. B Whether I increases or decreases, B will not experience any force
  3. C If I increases, A will repel B
  4. D If I increases, A will attract B
Show answer

Correct answer: C

8
The current flows in a circuit as shown below.
Electromagnetic Induction – NEET-20167 If a second circuit is brought near the first circuit then the current in the second circuit will be :-
  1. A Clock wise
  2. B Anti clock wise
  3. C Depending on the value of R$_{G}$
  4. D None of the above
Show answer

Correct answer: B

9
A coil of mean area $500 \mathrm {~cm} ^ { 2 }$ and having 1000 turns is held perpendicular to a uniform field of 0.4 gauss. The coil is turned through $180 ^ { \circ }$ in $\frac { 1 } { 10 }$ second. The average induced e.m.f. :-
  1. A 0.04 V
  2. B 0.4 V
  3. C 4 V
  4. D 0.004 V
Show answer & explanation

Correct answer: A

$\begin{aligned} \varepsilon & =\frac{2 \mathrm{NBA}}{\mathrm{t}} \\ & =\frac{1000 \times\left(0.4 \times 10^{-4}\right) \times\left(500 \times 10^{-4}\right) \times 2}{0.1} \\ & =0.04 \mathrm{~V}\end{aligned}$
10
'SI' unit of magnetic flux is:-
  1. A ampere/meter ${ } ^ { 2 }$
  2. B weber
  3. C gauss
  4. D oersted
Show answer

Correct answer: B

11
An electron beam is moving near to a conducting loop then the induced current in the loop :-
  1. A clockwise
  2. B anticlockwise
  3. C both
  4. D no current
Show answer & explanation

Correct answer: D

Speed of beam is constant so current is also constant.
Due to this no current induced.
∵ v = constant
⇒ I = constant
⇒ φ = constant
⇒ $\frac{\mathrm{d} \phi}{\mathrm{dt}}=0$
⇒ ε = 0
12
Consider a metal ring kept on a horizontal plane. A bar magnet is held above the ring with its length along the axis of the ring. If the magnet is dropped freely the acceleration of the falling magnet is (g is acceleration due to gravity):-
Electromagnetic Induction – NEET-20180
  1. A More than g
  2. B Equal to g
  3. C Less than g
  4. D Depend on mass of magnet
Show answer

Correct answer: C

13
Magnetic field through a coil is changed with respect to time and an emf is induced in it. Select the incorrect statement regarding induced emf in coil :-
  1. A Coil may be made up with wood
  2. B Coil may be connected with an open circuit
  3. C Coil must be of conducting nature
  4. D Induced emf does not depends upon resistance of the coil
Show answer

Correct answer: C

14
If number of turns of $70 \mathrm {~cm} ^ { 2 }$ coil is 200 and it is placed in a magnetic field of $0.8 \mathrm {~Wb} / \mathrm { m } ^ { 2 }$ which is perpendicular to the plane of coil and it is rotated through an angle $180 ^ { \circ }$ in 0.1 sec , then induced emf in coil :-
  1. A 11.2 V
  2. B 1.12 V
  3. C 22.4 V
  4. D 2.24 V
Show answer & explanation

Correct answer: C

Electromagnetic Induction – NEET-20187
15
A closed coil consists of 500 turns on a rectangular frame of area $4.0 \mathrm {~cm} ^ { 2 }$ and has a resistance of 50 ohms. The coil is kept with its plane perpendicular to a uniform magnetic field of $0.2 \mathrm { wb } / \mathrm { m } ^ { 2 }$, the amount of charge flowing through the coil if it is turned over (rotated through $180 ^ { \circ }$ ):-
  1. A $1.6 \times 10 ^ { - 3 } \mathrm { C }$
  2. B $16 \times 10 ^ { - 3 } \mathrm { C }$
  3. C $0.16 \times 10 ^ { - 3 } \mathrm { C }$
  4. D $160 \times 10 ^ { - 3 } \mathrm { C }$
Show answer & explanation

Correct answer: A

$\mathrm{q}=\frac{\Delta \phi}{\mathrm{R}}=\frac{2 \mathrm{NBA}}{\mathrm{R}}$
16
A coil of resistance 10 Ω and 1000 turns have the magnetic flux line of $5.5 \times 10 ^ { - 4 } \mathrm {~Wb}$. If the magnetic flux changed to $5 \times 10 ^ { - 4 } \mathrm {~Wb}$. in 0.1 sec , then the induced charge in coil is :-
  1. A 50 μC
  2. B 5 μC
  3. C 2 μC
  4. D 20 μC
Show answer & explanation

Correct answer: B

$\mathrm{q}=\frac{\Delta \phi}{\mathrm{R}}=\frac{5.5 \times 10^{-4}-5 \times 10^{-4}}{10}=5 \times 10^{-6} \mathrm{C}$
17
A square loop of side 22 cm is changed to a circle in time 0.4 s. The magnetic field present is 0.2 T. The emf induced is :-
  1. A -6.6 mV
  2. B -13.2 mV
  3. C +6.6 mV
  4. D +13.2 mV
Show answer & explanation

Correct answer: A

Electromagnetic Induction – NEET-20175
18
When the current through a solenoid increases at a constant rate, the induced current
  1. A is a constant and is in the direction of the inducing current
  2. B is a constant and is opposite to the direction of the inducing current
  3. C increase with time and is in the direction of the inducing current
  4. D increase with time and opposite to the direction of the inducing current
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Correct answer: B

19
The magnetic flux through a circuit of resistance R changes by an amount $\Delta \phi$ in a time $\Delta \mathrm { t }$. The total quantity of electric charge Q that passes any point in the circuit during the time $\Delta t$ is represented by:-
  1. A $\mathrm { Q } = \frac { \Delta \phi } { \mathrm { R } }$
  2. B $\mathrm { Q } = \frac { \Delta \phi } { \Delta \mathrm { t } }$
  3. C $\mathrm { Q } = \mathrm { R } \cdot \frac { \Delta \phi } { \Delta \mathrm { t } }$
  4. D $\mathrm { Q } = \frac { 1 } { \mathrm { R } } \cdot \frac { \Delta \phi } { \Delta \mathrm { t } }$
Show answer & explanation

Correct answer: A

$\mathrm{q}=\frac{\Delta \phi}{\mathrm{R}}$
$\therefore \mathrm{q} \propto(\Delta \mathrm{t})^{\circ}$
20
The current flows from A to B as shown in the figure. The direction of the induced current in the loop is :-
Electromagnetic Induction – NEET-20182
  1. A clockwise
  2. B anticlockwise
  3. C straight line
  4. D none of these
Show answer & explanation

Correct answer: D

The current in wire is constant so flux is also constant
I = const
⇒ B = const
⇒ φ = constant
⇒ NO EMI

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