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Physics M.C.Q (1 Marks)

Electromagnetic Induction · MP Board (MPBSE) STD 12 Science (Madhya Pradesh - English Medium). 356 questions.

Questions · Page 4 of 8

M.C.Q (1 Marks)

MCQ 1511 Mark
If the current 30 A flowing in the primary coil is made zero in 0.1 sec. The emf induced in the secondary coil is 1.5 volt. The mutual inductance between the coil is
  • ✓
    0.05 H
  • B
    1.05 H
  • C
    0.1 H
  • D
    0.2 H
Answer
Correct option: A.
0.05 H
 0.05 H
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MCQ 1521 Mark
The device that does not work on the principle of mutual induction is
  • A
    Induction coil
  • B
    Motor
  • ✓
    Tesla coil
  • D
    Transformer
Answer
Correct option: C.
Tesla coil
  Tesla coil
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MCQ 1531 Mark
The pointer of a dead-beat galvanometer gives a steady deflection because
  • ✓
    Eddy currents are produced in the conducting frame over which the coil is wound
  • B
    Its magnet is very strong
  • C
    Its pointer is very light
  • D
    Its frame is made of abonite
Answer
Correct option: A.
Eddy currents are produced in the conducting frame over which the coil is wound
 Eddy currents are produced in the conducting frame over which the coil is wound
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MCQ 1541 Mark
The core of a transformer is laminated to reduce energy losses due to
  • ✓
    Eddy currents
  • B
    Hysteresis
  • C
    Resistance in winding
  • D
    None of these
Answer
Correct option: A.
Eddy currents
 Eddy currents
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MCQ 1551 Mark
Which of the following is not an application of eddy currents
  • A
    Induction furnace
  • B
    Galvanometer damping
  • C
    Speedometer of automobiles
  • ✓
    X-ray crystallography
Answer
Correct option: D.
X-ray crystallography
 X-ray crystallography
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MCQ 1561 Mark
Use of eddy currents is done in the following except
  • A
    Moving coil galvanometer
  • B
    Electric brakes
  • C
    Induction motor
  • ✓
    Dynamo
Answer
Correct option: D.
Dynamo
 Dynamo
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MCQ 1571 Mark
Plane of eddy currents makes an angle with the plane of magnetic lines of force equal to
  • A
    40°
  • B
    0°
  • ✓
    90°
  • D
    180°
Answer
Correct option: C.
90°
 90°
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MCQ 1581 Mark
Which of the following is constructed on the principle of electromagnetic induction
  • A
    Galvanometer
  • B
    Electric motor
  • ✓
    Generator
  • D
    Voltmeter
Answer
Correct option: C.
Generator
 Generator
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MCQ 1591 Mark
A transformer is based on the principle of
  • ✓
    Mutual inductance
  • B
    Self inductance
  • C
    Ampere's law
  • D
    Lenz's law
Answer
Correct option: A.
Mutual inductance
  Mutual inductance
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MCQ 1601 Mark
A coil having an inductance of 0.5 H carries a current which is uniformly varying from zero to 10 ampere in 2 second. The e.m.f. (in volts) generated in the coil is
  • A
    10
  • B
    5
  • ✓
    2.5
  • D
    1.25
Answer
Correct option: C.
2.5
 2.5
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MCQ 1611 Mark
The square root of the product of inductance and capacitance has the dimension of
  • A
    Length
  • B
    Mass
  • ✓
    Time
  • D
    No dimension
Answer
Correct option: C.
Time
 Time
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MCQ 1621 Mark
An oscillator circuit consists of an inductance of 0.5mH and a capacitor of 20 μF. The resonant frequency of the circuit is nearly
  • A
    15.92 Hz
  • B
    159.2 Hz
  • ✓
    1592 Hz
  • D
    15910 Hz
Answer
Correct option: C.
1592 Hz
 1592 Hz
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MCQ 1631 Mark
A LC circuit is in the state of resonance. If C = 0.1μF and L = 0.25 henry. Neglecting ohmic resistance of circuit what is the frequency of oscillations
  • ✓
    1007 Hz
  • B
    100 Hz
  • C
    109 Hz
  • D
    500 Hz
Answer
Correct option: A.
1007 Hz
 1007 Hz
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MCQ 1641 Mark
The time constant of an LR circuit represents the time in which the current in the circuit
  • A
    Reaches a value equal to about 37% of its final value
  • ✓
    Reaches a value equal to about 63% of its final value
  • C
    Attains a constant value
  • D
    Attains 50% of the constant value
Answer
Correct option: B.
Reaches a value equal to about 63% of its final value
 Reaches a value equal to about 63% of its final value
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MCQ 1651 Mark
An inductor, L a resistance R and two identical bulbs, $B_1$ and $B_2$ are connected to a battery through a switch S as shown in the figure. The resistance R is the same as that of the coil that makes L. Which of the following statements gives the correct description of the happenings when the switch S is closed
  • A
    The bulb $B_2$ lights up earlier than $B_1$ and finally both the bulbs shine equally bright
  • B
    $B_1$ light up earlier and finally both the bulbs acquire equal brightness
  • ✓
    $B_2$ lights up earlier and finally $B_1$ shines brighter than $B_2$
  • D
    $B_1$ and $B_2$ light up together with equal brightness all the time
Answer
Correct option: C.
$B_2$ lights up earlier and finally $B_1$ shines brighter than $B_2$
(c) $B_2$ lights up earlier and finally $B_1$ shines brighter than $B_2$
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MCQ 1661 Mark
A solenoid has an inductance of 60 henrys and a resistance of 30 ohms. If it is connected to a 100 volt battery, how long will it take for the current to reach $\frac{e-1}{e} \approx 63.2 \%$ of its final value
  • A
    1 second
  • ✓
    2 seconds
  • C
    e seconds
  • D
    2e seconds
Answer
Correct option: B.
2 seconds
(b) 2 seconds
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MCQ 1671 Mark
A coil of inductance 40 henry is connected in 0series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is
  • A
    40 seconds
  • B
    20 seconds
  • C
    8 seconds
  • ✓
    5 seconds
Answer
Correct option: D.
5 seconds
 5 seconds
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MCQ 1681 Mark
A capacitor is fully charged with a battery. Then the battery is removed and coil is connected with the capacitor in parallel, current varies as
  • A
     Increases monotonically
  • B
     Decreases monotonically
  • C
     Zero
  • ✓
     Oscillates indefinitely
Answer
Correct option: D.
 Oscillates indefinitely
Oscillates indefinitely
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MCQ 1691 Mark
In the figure magnetic energy stored in the coil is
  • A
    Zero
  • B
    Infinite
  • ✓
    25 joules
  • D
    None of the above
Answer
Correct option: C.
25 joules
(c) 25 joules
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MCQ 1701 Mark
In an LR-circuit, time constant is that time in which current grows from zero to the value (where $I_0$ is the steady state current)
  • ✓
    0.63 $I_0$
  • B
    0.50 $I_0$
  • C
    0.37 $I_0$
  • D
    $I_0$
Answer
Correct option: A.
0.63 $I_0$
(a) 0.63 $I_0$
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MCQ 1711 Mark
An inductance L and a resistance R are first connected to a battery. After some time the battery is disconnected but L and R remain connected in a closed circuit. Then the current reduces to 37% of its initial value in
  • A
    RL sec
  • B
    $\frac{R}{L}$sec
  • ✓
    $\frac{L}{R}$sec
  • D
    $\frac{1}{LR}$sec
Answer
Correct option: C.
$\frac{L}{R}$sec
(c) $\frac{L}{R}$sec
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MCQ 1721 Mark
In L-R circuit, for the case of increasing current, the magnitude of current can be calculated by using the formula
  • A
    $\mathrm{I}=\mathrm{I}_0 \mathrm{e}^{-\mathrm{Rt} / \mathrm{L}}$
  • ✓
    $\mathrm{I}=\mathrm{I}_0\left(1-\mathrm{e}^{-\mathrm{Rt} / \mathrm{L}}\right)$
  • C
    $\mathrm{I}=\mathrm{I}_0\left(1-\mathrm{e}^{\mathrm{Rt} / \mathrm{L}}\right)$
  • D
    $\mathrm{I}=\mathrm{I}_0 \mathrm{e}^{\mathrm{Rt} / \mathrm{L}}$
Answer
Correct option: B.
$\mathrm{I}=\mathrm{I}_0\left(1-\mathrm{e}^{-\mathrm{Rt} / \mathrm{L}}\right)$
(b) $\mathrm{I}=\mathrm{I}_0\left(1-\mathrm{e}^{-\mathrm{Rt} / \mathrm{L}}\right)$
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MCQ 1731 Mark
The adjoining figure shows two bulbs $B_1$ and $B_2$ resistor R and an inductor L. When the switch S is turned off
  • A
    Both $B_1$ and $B_2$ die out promptly
  • B
    Both $B_1$ and $B_2$ die out with some delay
  • ✓
    $B_1$ dies out promptly but $B_2$ with some delay
  • D
    $B_2$ dies out promptly but $B_1$ with some delay
Answer
Correct option: C.
$B_1$ dies out promptly but $B_2$ with some delay
(c) $B_1$ dies out promptly but $B_2$ with some delay
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MCQ 1741 Mark
Eddy currents are used in
  • A
     Induction furnace
  • B
     Electromagnetic brakes
  • C
     Speedometers
  • ✓
     All of these
Answer
Correct option: D.
 All of these
 All of these
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MCQ 1751 Mark
Two coils A and B having turns 300 and 600 respectively are placed near each other, on passing a current of 3.0 ampere in A, the flux linked with A is $1.2 \times 10^{-4}$ weber and with B it is $9.0 \times 10^{-5}$ weber. The mutual inductance of the system is
  • A
    $2 \times 10^{-5}$ henry
  • ✓
    $3 \times 10^{-5}$ henry
  • C
    $4 \times 10^{-5}$ henry
  • D
    $6 \times 10^{-5}$ henry
Answer
Correct option: B.
$3 \times 10^{-5}$ henry
(b) $3 \times 10^{-5}$ henry
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MCQ 1761 Mark
Two identical induction coils each of inductance $L$ joined in series are placed very close to each other such that the winding direction of one is exactly opposite to that of the other, what is the net inductance
  • A
    $L^2$
  • B
    $2L$
  • C
    $L/2$
  • ✓
    Zero
Answer
Correct option: D.
Zero
Zero
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MCQ 1771 Mark
The resistance and inductance of series circuit are 5$\Omega$ and 20H respectively. At the instant of closing the switch, the current is increasing at the rate 4A - s. The supply voltage is
  • A
    20 V
  • ✓
    80 V
  • C
    120 V
  • D
    100 V
Answer
Correct option: B.
80 V
(b) 80 V
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MCQ 1781 Mark
The current through choke coil increases form zero to 6A in 0.3 seconds and an induced e.m.f. of 30 V is produced. The inductance of the coil of choke is
  • A
     5 H
  • B
     2.5 H
  • ✓
    1.5 H
  • D
     2 H
Answer
Correct option: C.
1.5 H
1.5 H
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MCQ 1791 Mark
The current in a coil decreases from 1 A to 0.2 A. In 10sec. Calculate the coefficient of self inductance. If induced emf is 0.4 volt.
  • ✓
    5 H
  • B
    3 H
  • C
    4 H
  • D
    2 H
Answer
Correct option: A.
5 H
5 H
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MCQ 1801 Mark
Two circular coils have their centres at the same point. The mutual inductance between them will be maximum when their axes
  • ✓
    Are parallel to each other
  • B
    Are at $60^\circ$ to each other
  • C
    Are at $45^\circ$ to each other
  • D
    Are perpendicular to each other
Answer
Correct option: A.
Are parallel to each other
Are parallel to each other
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MCQ 1811 Mark
Why the current does not rise immediately in a circuit containing inductance
  • ✓
    Because of induced emf
  • B
    Because of high voltage drop
  • C
    Because of low power consumption
  • D
    Because of Joule heating
Answer
Correct option: A.
Because of induced emf
 Because of induced emf
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MCQ 1821 Mark
A solenoid of length l metre has self-inductance L henry. If number of turns are doubled, its self inductance
  • A
    Remains same
  • B
    Becomes 2L henry
  • ✓
    Becomes 4L henry
  • D
    Becomes $\frac{\mathrm{L}}{\sqrt{2}}$ henry
Answer
Correct option: C.
Becomes 4L henry
(c) Becomes 4L henry
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MCQ 1831 Mark
Energy stored in a coil of self inductance 40mH carrying a steady current of 2 A is
  • A
     0.8 J
  • B
     8 J
  • ✓
     0.08 J
  • D
     80 J
Answer
Correct option: C.
 0.08 J
 0.08 J
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MCQ 1841 Mark
If a change in current of 0.01 A in one coil produces a change in magnetic flux of $1.2 \times 10^{-2} \mathrm{wb}$ in the other coil, then the mutual inductance of the two coils in henries is
  • A
    0
  • B
    0.5
  • ✓
    1.2
  • D
    3
Answer
Correct option: C.
1.2
(c) 1.2
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MCQ 1851 Mark
A coil of resistance 10 W and an inductance 5H is connected to a 100 volt battery. Then energy stored in the coil is
  • A
    125 erg
  • B
    125 J
  • C
     250 erg
  • ✓
     250 J
Answer
Correct option: D.
 250 J
250 J
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MCQ 1861 Mark
An average induced e.m.f. of 1V appears in a coil when the current in it is changed from 10A in one direction to 10 A in opposite direction in 0.5 sec. Self-inductance of the coil is
  • ✓
     25 mH
  • B
     50 mH
  • C
     75 mH
  • D
     100 mH
Answer
Correct option: A.
 25 mH
 25 mH
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MCQ 1871 Mark
A coil resistance 20W and inductance 5H is connected with a 100V battery. Energy stored in the coil will be
  • A
    41.5 J
  • ✓
    62.50 J
  • C
     125 J
  • D
    250 J
Answer
Correct option: B.
62.50 J
 62.50 J
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MCQ 1881 Mark
When the current change from + 2A to – 2A in 0.05 second, an e.m.f. of 8 V is induced in a coil. The coefficient of self-induction of the coil is
  • ✓
    0.1 H
  • B
     0.2 H
  • C
     0.4 H
  • D
    0.8 H
Answer
Correct option: A.
0.1 H
 0.1 H
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MCQ 1891 Mark
Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon
  • A
     The currents in the two coils
  • B
     The rates at which currents are changing in the two coils
  • ✓
     Relative position and orientation of the two coils
  • D
     The materials of the wires of the coils
Answer
Correct option: C.
 Relative position and orientation of the two coils
Relative position and orientation of the two coils
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MCQ 1901 Mark
An L-R circuit has a cell of e.m.f. E, which is switched on at time t = 0. The current in the circuit after a long time will be
  • A
    Zero
  • ✓
    $\frac{E}{R}$
  • C
    $\frac{E}{L}$
  • D
    $\frac{E}{\sqrt{L^2+R^2}}$
Answer
Correct option: B.
$\frac{E}{R}$
(b) $\frac{E}{R}$
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MCQ 1911 Mark
An air core solenoid has $1000$ turns and is one metre long. Its cross$-$sectional area is $10\ cm^2$. Its self inductance is
  • A
    $0.1256 \ mH$
  • B
    $12.56 \ mH$
  • ✓
    $1.256 \ mH$
  • D
    $125.6 \ mH$
Answer
Correct option: C.
$1.256 \ mH$
$1.256 \ mH$
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MCQ 1921 Mark
Two circuits have mutual inductance of 0.1 H. What average e.m.f. is induced in one circuit when the current in the other circuit changes from 0 to 20 A in 0.02 s
  • A
     240 V
  • B
    230 V
  • ✓
     100 V
  • D
     300 V
Answer
Correct option: C.
 100 V
100 V
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MCQ 1931 Mark
The self-induced e.m.f. in a 0.1 H coil when the current in it is changing at the rate of 200 ampere/second is
  • A
    $8 \times 10^{-4} \mathrm{~V}$
  • B
    $8 \times 10^{-5} \mathrm{~V}$
  • ✓
    20 V
  • D
    125 V
Answer
Correct option: C.
20 V
(c) 20 V
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MCQ 1941 Mark
The current in a coil of inductance 5 H decreases at the rate of 2 A/s. The induced e.m.f. is
  • A
     2 V
  • B
    5 V
  • ✓
     10 V
  • D
    – 10 V
Answer
Correct option: C.
 10 V
10 V
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MCQ 1951 Mark
In circular coil, when no. of turns is doubled and resistance becomes $\frac{1}{4}$ th of initial, then inductance becomes 
  • ✓
    4 times
  • B
    2 times
  • C
    8 times
  • D
    No change
Answer
Correct option: A.
4 times
(a) 4 times
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MCQ 1961 Mark
A coil of $100$ turns carries a current of $5 \ mA$ and creates a magnetic flux of $10^{-5}$ weber. the inductance is
  • A
    $0.2 \ mH$
  • ✓
    $2.0 \ mH$
  • C
    $0.02 \ mH$
  • D
    None of these
Answer
Correct option: B.
$2.0 \ mH$
$2.0 \ mH$
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MCQ 1971 Mark
Which of the following is not the unit of self inductance
  • A
    Weber$/$Ampere
  • B
    Ohm$-$Second
  • ✓
    Joule$-$Ampere
  • D
    Joule Ampere$^{-2}$
Answer
Correct option: C.
Joule$-$Ampere
Joule$-$Ampere
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MCQ 1981 Mark
Find out the e.m.f. produced when the current changes from 0 to 1 A in 10 second, given L = 10 mH
  • A
    1 V
  • ✓
    1 mV
  • C
     1 mV
  • D
     0.1 V
Answer
Correct option: B.
1 mV
1 mV
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MCQ 1991 Mark
Pure inductance of 3.0 H is connected as shown below. The equivalent inductance of the circuit is
  • ✓
    1 H
  • B
    2 H
  • C
    3 H
  • D
    9 H
Answer
Correct option: A.
1 H
(a) 1 H
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MCQ 2001 Mark
The current in a coil changes from 4 ampere to zero in 0.1 s. If the average e.m.f. induced is 100 volt, what is the self inductance of the coil
  • ✓
     2.5 H
  • B
     25 H
  • C
     400 H
  • D
     40 H
Answer
Correct option: A.
 2.5 H
2.5 H
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M.C.Q (1 Marks) - Page 4 - Physics STD 12 Science Questions - Vidyadip