MCQ 11 Mark
The device is based on the principle of mutual induction is:
- Aac generator
- Bgalvanometer
- Cvoltmeter
- ✓transformer
Answer
View full question & answer→Correct option: D.
transformer
(d)transformer
Questions
M.C.Q [1M]
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36 questions · timed · auto-graded
MCQ 21 Mark
In the given figure, an electron is moving from A to B. The direction of A induced current in the loop is:
- ✓First anticlockwise and then clockwise after crossing C
- BFirst clockwise and then anticlockwise after crossing C
- CAnticlockwise
- DClockwise
Answer
View full question & answer→Correct option: A.
First anticlockwise and then clockwise after crossing C
(a)First anticlockwise and then clockwise after crossing C
MCQ 31 Mark
A rectangular coil is rotating with a uniform angular velocity between magnetic poles. The correct graph of change of magnetic flux $\phi$ passing through the coil and induced emf (c) with time is :
- A
- B
- ✓
- D
Answer
View full question & answer→Correct option: C.
(c )
MCQ 41 Mark
A coil of copper and a wire AB are located in the plane of the paper as shown in the figure. If current I flowing through the wire is increasing, then the direction of induced current in the coil is:
- AAnticlockwise
- ✓Clockwise
- CNo induced current will be generated
- DNone of the above
Answer
View full question & answer→Correct option: B.
Clockwise
(b)Clockwise
MCQ 51 Mark
Lenz's law gives:
- AMagnitude of induced emf
- ✓Direction of induced current
- CBoth direction and magnitude of induced current
- DMagnitude of induced current
Answer
View full question & answer→Correct option: B.
Direction of induced current
(b)Direction of induced current
MCQ 61 Mark
Direction of induced emf is determined by:
- AAmpere's law
- BFleming's left hand rule
- CFleming's right hand rule
- ✓Lenz's law
Answer
View full question & answer→Correct option: D.
Lenz's law
(d)Lenz's law
MCQ 71 Mark
A square loop of side 22 cm is converted into circular loop of 0.45. If uniform magnetic field of 0.2 T is perpendicular to the loop, then induced electromotive force in the loop is:
- ✓$6.6 \times 10^{-3} V$
- B$6.6 \times 10^{-5} V$
- C$4.6 \times 10^{-4} V$
- D$4.60 \times 10^{-8} V$
Answer
View full question & answer→Correct option: A.
$6.6 \times 10^{-3} V$
(a)$6.6 \times 10^{-5} V$
MCQ 81 Mark
A square coil of area $10^{-2} m^2$ is kept perpendicular in a magnetic field of intensity $10^3 Wb / m ^2$. The magnitude of magnetic flux passing through the square is :
- ✓10 Wb
- B$10^{-5} Wb$
- C$10^{5} Wb$
- D100 Wb
Answer
View full question & answer→Correct option: A.
10 Wb
(a)10 Wb
MCQ 91 Mark
A coil of 40 turns and area $4 cm^2$ is suddenly removed from a magnetic field. Charge of $2 \times 10^{-4} C$ flows through it. If its resistance is 80 ohms, then magnetic flux density is:
- A0.5
- ✓1
- C1.5
- D2
Answer
View full question & answer→Correct option: B.
1
(b)1
MCQ 101 Mark
In a circuit of resistance $R$, magnetic flux $\Delta \phi$ changes in time $\Delta t$. Total charge $Q$ flowing through the circuit in time $\Delta r$ is :
- A$Q=\frac{\Delta \phi}{\Delta t}$
- B$Q =\frac{\Delta \phi}{\Delta t} \times R$
- C$Q=\frac{-\Delta \phi}{\Delta t} \times R$
- ✓$Q =\frac{\Delta \phi}{ R }$
Answer
View full question & answer→Correct option: D.
$Q =\frac{\Delta \phi}{ R }$
(d)$Q =\frac{\Delta \phi}{ R }$
MCQ 111 Mark
The self-inductance of a coil will be less when:
- ACurrent flowing through the coil is less
- BMagnetic field is very weak
- CPlane of coil is along the magnetic field
- ✓Coil is wound on a diamagnetic substance
Answer
View full question & answer→Correct option: D.
Coil is wound on a diamagnetic substance
(d)Coil is wound on a diamagnetic substance
MCQ 121 Mark
Transformer is based on the principle of:
- AMagnetic induction
- BElectromagnetic induction
- CSelf-inductance
- ✓None of the above
Answer
View full question & answer→Correct option: D.
None of the above
(d)None of the above
MCQ 131 Mark
In a induction coil, when current changes from 3 A to 2 A in 1 milli second, there is electric vapor of 5 volt. The self-inductance of the coil is:
- AZero
- ✓5 m H
- C5 KH
- D5 H
Answer
View full question & answer→Correct option: B.
5 m H
(b)5 m H
MCQ 141 Mark
Mutual inductance of two coils is M. If current change in time t in first coil is I, then induced emf in the second coil is:
- A$Ml t$
- ✓$\frac{ MI }{t}$
- C$\frac{ M t}{ I }$
- D$\frac{i}{ MI t}$
Answer
View full question & answer→Correct option: B.
$\frac{ MI }{t}$
(b)$\frac{ MI }{t}$
MCQ 151 Mark
A square loop of side l is moving with a constant velocity v in a uniform magnetic field. The magnitude of induced emf is:
- ✓vBl
- B$\frac{ B l}{v}$
- C$\frac{vl}{B}$
- Dzero
Answer
View full question & answer→Correct option: A.
vBl
(a)vBl
MCQ 161 Mark
Dimensions of coefficient of self-inductance is :
- A$ML ^2 T^{-3} A^{-2}$
- B$M ^2 LT ^{-2} A^{-2}$
- C$M ^0 L^2 T^{-3} A^{-2}$
- ✓$ML ^2 T^{-2} A^{-2}$
Answer
View full question & answer→Correct option: D.
$ML ^2 T^{-2} A^{-2}$
(d)$ML ^2 T^{-2} A^{-2}$
MCQ 171 Mark
Mutual inductance of two coils placed near is 4.0 H (Henry). If current in the primary coil decreases from 5 A to zero in $10^{-2}$ seconds, then magnitude of induced emf in secondary coil is :
- A0.20 volt
- ✓-2000 volt
- C2000 volt
- D-0.20 volt
Answer
View full question & answer→Correct option: B.
-2000 volt
(b)-2000 volt
MCQ 181 Mark
Two coils are kept close to each other. The factor on which the coefficient of mutual inductance for pair of coils depends:
- ARate of change of current in both the coils
- ✓On relative position of both the coils
- COn the material of wire of both the coils
- DOn current in both the coils
Answer
View full question & answer→Correct option: B.
On relative position of both the coils
(b)On relative position of both the coils
MCQ 191 Mark
A metallic rod of length $l$ is kept perpendicular to a magnetic field and it is rotated on a circular path with frequency $f$. The potential difference across the ends of the rod is :
- A$\frac{ B }{f}$
- B$\frac{\pi l^2 B}{f}$
- C$\frac{ B l}{f}$
- ✓$\pi l^2 B f$
Answer
View full question & answer→Correct option: D.
$\pi l^2 B f$
(d)$\pi l^2 B f$
MCQ 201 Mark
The instantaneous magnitude of magnetic flux associated with a closed circuit of $5 \Omega$ resistance is given by $\phi_{ B }=6 t^2-5 t+1$, then magnitude of induced current (in A ) in the circuit at $t =0.25$ second is :
- A2.4
- B1.6
- ✓0.4
- D1.2
Answer
View full question & answer→Correct option: C.
0.4
(c )0.4
MCQ 211 Mark
In the given figure, a current of constant magnitude is flowing in the wire AB. Direction of induced current flowing through the wire is:
- AAnticlockwise
- BClockwise
- ✓Induced current will not flow
- DNone of the above
Answer
View full question & answer→Correct option: C.
Induced current will not flow
(c )Induced current will not flow
MCQ 221 Mark
Out of the following, which does not have dimension $\left[ M ^1 L^2 T^{-3} A^{-1}\right] ;$
- A$\int \overrightarrow{ E } \cdot \overrightarrow{ d l}$
- B$vB /$
- C$\frac{ d \phi_{ B }}{ dt }$
- ✓$\phi_{ B }$
Answer
View full question & answer→Correct option: D.
$\phi_{ B }$
(d)$\phi_{ B }$
MCQ 231 Mark
A conducting loop is kept in a uniform magnetic field such that its plane is perpendicular to the magnetic field. Induced emf will be generated in the loop if:
- ASpeed of loop in the field is transferable
- BLoop should rotate on its axis
- ✓Loop should rotate relative to its diameter
- DNone of the above
Answer
View full question & answer→Correct option: C.
Loop should rotate relative to its diameter
(c )Loop should rotate relative to its diameter
MCQ 241 Mark
If instantaneous magnetic flux in a coil is $BA \cos \omega t$, then magnitude of induced emf in the coil is :
- A$\frac{ BA }{\omega} \sin \omega t$
- B$B \frac{\omega}{ A } \sin \omega t$
- ✓$BA \omega \sin \omega t$
- D$BA \cos \omega t$
Answer
View full question & answer→Correct option: C.
$BA \omega \sin \omega t$
(c )$BA \omega \sin \omega t$
MCQ 251 Mark
A copper ring is kept horizontal and a bar of magnet is dropped in the direction of the axis of the ring. The acceleration of the falling magnet will be:
- AEqual to the gravitational acceleration
- ✓Less than the gravitational acceleration
- CMore than the gravitational acceleration
- DNone of the above
Answer
View full question & answer→Correct option: B.
Less than the gravitational acceleration
(b)Less than the gravitational acceleration
MCQ 261 Mark
A square conducting loop of side L and resistance R is moving in its plane with a uniform velocity v perpendicular to its one side, where magnetic induction is B which is constant in space and time and is normal to the inwards of the plane. Induced current in the coil is:
- A$\frac{ B / v}{ R }$ clockwise
- B$\frac{2 B / y }{ R }$ anticlockwise
- C$\frac{ B / v}{ R }$ anticlockwise
- ✓zero
Answer
View full question & answer→Correct option: D.
zero
(d)zero
MCQ 271 Mark
According to the figure, a conducting wire AB (length $l)$ is moving with a velocity v on two parallel rails P and Q. A uniform magnetic field is applied normally inwards to the plane of rails. Essential force needed to keep the velocity of the bar constant is:
- ✓Zero
- BI/B
- C$I / B \sin \theta$
- DNone of these
Answer
View full question & answer→Correct option: A.
Zero
(a)Zero
MCQ 281 Mark
Which of the following will produce maximum electromotive force?
- A50 A dc
- B50 A 50 Hz ac
- ✓50 A 500 Hz ac
- D100 A dc
Answer
View full question & answer→Correct option: C.
50 A 500 Hz ac
(c )50 A 500 Hz ac
MCQ 291 Mark
In the given figure, when key k is closed, then direction of induced current in the coil B IS:
- ✓Anticlockwise, momentarily
- BClockwise, momentarily
- CAnticlockwise and continuous
- DClockwise and continuous
Answer
View full question & answer→Correct option: A.
Anticlockwise, momentarily
(a)Anticlockwise, momentarily
MCQ 301 Mark
In the given figure, conducting rod AB is moved in the direction of magnetic field developed by the current carrying conductor MN. The direction of generated induced current will be:
- ✓$A \rightarrow B$
- B$B \rightarrow A$
- CInduced current will not be generated
- DNone of the above
Answer
View full question & answer→Correct option: A.
$A \rightarrow B$
(a)$A \rightarrow B$
MCQ 311 Mark
A wire 2 m long is moving with velocity of $1 m / s$ perpendicular to a magnetic field of $0.5 Wb / m ^2$. The magnitude of induced cmf in it is :
- A0.5 V
- B2 V
- C0.1 V
- ✓1 V
Answer
View full question & answer→Correct option: D.
1 V
(d)1 V
MCQ 321 Mark
The surface shown in the figure does not represent:
- AMagnetic field
- ✓Static electric field
- CInduced electric field
- DGravitational field
Answer
View full question & answer→Correct option: B.
Static electric field
(b)Static electric field
MCQ 331 Mark
Flux associated to a coil at any instant $t$ is $\phi=10 r^2$ $50 t+250$, then induced emf at $t =3$ is :
- A190 V
- B-190 V
- ✓-10 V
- D10 V
Answer
View full question & answer→Correct option: C.
-10 V
(c )-10V
MCQ 341 Mark
The Lenz's law is based on which of the following physical quantity?
- ACharge
- BMomentum
- CMass
- ✓Energy
Answer
View full question & answer→Correct option: D.
Energy
(d)Energy
MCQ 351 Mark
Which of the following unit is not free from error?
- A$\frac{ Wb }{ A }$
- ✓$\frac{V-s}{A^2}$
- C$\frac{ J }{ A ^2}$
- D$\Omega- s$
Answer
View full question & answer→Correct option: B.
$\frac{V-s}{A^2}$
(b)$\frac{V-s}{A^2}$
MCQ 361 Mark
Coefficient of mutual inductance between two coils is 2.5 H . If current is changing in one coil at the rate of 1 $A / s$, then magnitude of induced emf in the secondary coil : $\quad \begin{array}{ll} & 0\end{array}$
- A2.5 m V
- ✓2.5 V
- C2.5 m
- DZero
Answer
View full question & answer→Correct option: B.
2.5 V
(b)2.5 V