WorksheetsMAGNETISM &EMI
Total questions: 20
Worksheet time: 25mins
Mutual inductance of two coils can be increased by
Decreasing the number of turns in the coil
Increasing the number of turns in the coil
Winding the coils on wooden cores
None of these
A pair of adjacent coil has a mutual inductance of 2.5 H. If the current in one coil changes from 0 to 40 A in 0.8 s , then the change in flux linked with the other coil is
100 Wb
120 Wb
200 Wb
250 Wb
If the self inductance of 500 turns coil is 125 mH, then the self inductance of the similar coil of 800 turns is
48.8 mH
200 mH
290 mH
320 mH
Faraday's law are consequence of the conservation of
Charge
Energy
Magnetic field
both charge and magnetic field
The magnetic flux linked a coil of N turns of area of cross section A held its plane parallel to the field B is
NBA/2
NBA
NBA/4
ZERO
The dimensional formula of magnetic flux is
[ML2T2A-1]
[ML2T-2A-1]
[M-1L2T2A-1]
[ML-2T2A-1]
The magnetic flux linked with a coil, in webers is given by the equation Φ=6t2 + 4t +10. Then, the magnitude of induced emf, at t= 2 s will be
2 V
4 V
8 V
16 V
The direction of induced emf during electromagnetic induction is given by
Faraday's law
Lenz's law
Maxwell's law
Ampere's law
In a circuit with a coil of resistance 2 Ω , the magnetic flux changes from 2.0 Wb to 10.0 Wb in 0.2 s. The charge that flows in the coil during this time is
5.0 C
4.0 C
1.0 C
0.8 C
A conducting rod of length l is falling with a constant velocity v perpendicular to a uniform horizontal magnetic field B. A potential difference between its two ends will be
2Blv
Blv
Blv/2
B2l2v2
The closed loop (PQRS) of wire is moved into a uniform magnetic field at right angles to the plane of paper as shown in the figure. The direction of induced current in the coil is
PQRS
PSRQ
No curren is induced
None of the above
A wire of irregular shape turning into a circular shape. Using Lenz's law , the direction of induced current in the loop is
Clockwise
Anticlockwise
No current induced
None of these.
A constant current is flowing in a wire in the direction from X to Y. The direction of the induced current in the metallic loop no-1 is
Clack wise direction
Anti-clockwise direction
No current will flow through it.
None of these
Which of the following is not correct about the magnetic field lines?
The magnetic field lines of a magnet form continuous closed loop
The tangent to the field lines at a given point represents the direction of the net magnetic field B at that point.
The larger the number of field lines crossing per unit area , the stronger is the magnitude of the magnetic field B.
The magnetic filed lines may intersect to each other in certain conditions.
The net magnetic flux through any closed surface, kept in magnetic field is
Zero
μ0/4π
4πμ0
4μ0/π
A conductor is moving with velocity v in the magnetic field and induced current is I. If the velocity of conductor becomes double, the induced current will be
0.5 I
1.5 I
2I
2.5 I
Which of the following is not correct?
Whenever the amount of magnetic magnetic flux linked with a circuit changes, an emf is induced in the circuit.
The induced emf lasts so long as the change in magnetic flux continues.
The direction of induced emf is given by Lenz's law.
Lenz's law is a consequence of the law of conservation of momentum.
Which of the following does not use the application of eddy current?
Electric power meter
Induction furnace
LED light
Magnetic brakes in trains.
The coefficient of mutual induction of two coils depends on
medium between the coils
distance between the two coils
orientation of the two coils
all of these
The physical quantity which is measured in the unit of Wb A-1 is
Mutual inductance
Magnetic flux
Magnetic field
Electric flux.
