The current flowing in two coaxial coils in the same direction. On increasing the distance between the two, the electric current will ____.
Increase
Decrease
Remain unchanged
The information is incomplete
Lenz's law gives ____.
The magnitude of the induced e.m.f.
The direction of the induced current
Both the magnitude and direction of the induced current
The magnitude of the induced current
The north pole of a bar magnet is moved swiftly downward towards a closed coil and then second time it is raised upwards slowly. The magnitude and direction of the induced currents in the two cases is of ____.
First case Second case
Low value clockwise Higher value anticlockwise
First case Second case
Low value clockwise Equal value anticlockwise
First case Second case
Higher value clockwise Low value clockwise
First case Second case
Higher value anticlockwise Low value clockwise
A metallic ring connected to a rod oscillates freely like a pendulum. If now a magnetic field is applied in horizontal direction so that the pendulum now swings through the field, the pendulum wills ____.
Keep oscillating with the old time period
Keep oscillating with a smaller time period
Keep oscillating with a larger time period
Come to rest very soon
A circular coil of 500 turns of wire has an enclosed area of per turn. It is kept perpendicular to a magnetic field of induction 0.2 T and rotated by 180° about a diameter perpendicular to the field in 0.1 sec. How much charge will pass when the coil is connected to a galvanometer with a combined resistance of 50 ohms?
0.2 C
0.4 C
2 C
4 C
The direction of induced current is such that it opposes the very cause that has produced it. This is the law of ____.
Lenz
Faraday
Kirchoff
Fleming
To induce an e.m.f. in a coil, the linking magnetic fluxes ____.
Must decrease
Can either increase or decrease
Must remain constant
Must increase
A solenoid is 1.5 m long and its inner diameter is 4.0 cm. It has three layers of windings of 1000 turns each and carries a current of 2.0 amperes. The magnetic flux for a cross-section of the solenoid is nearly ____.
2.5 ( 10–7 weber
6.31 ( 10–6 weber
5.2 ( 10–5 weber
4.1 ( 10–5 weber
A coil of 40 (resistances has 100 turns and radius 6 mm is connected to ammeter of resistance of 160 ohms. Coil is placed perpendicular to the magnetic field. When coil is taken out of the field, 32 ( C charge flows through it. The intensity of magnetic field is ____.
6.55 T
5.66 T
0.655 T
0.566 T
Faraday's laws are consequence of conservation of ____.
Energy
Energy and magnetic field
Charge
Magnetic field