An electron moves along the line AB, which lies in the same plane as a circular loop of conducting wires as shown in the diagram. What will be the direction of current induced if any, in the loop
1. No current will be induced
2. The current will be clockwise
3. The current will be anticlockwise
4. The current will change direction as the electron passes by
A copper rod of length l is rotated about one end perpendicular to the magnetic field B with constant angular velocity . The induced e.m.f. between the two ends is
1. 1/2 B
2. 3/4 B
3. B
4. 2B
In the circuit shown below, the key K is closed at t=0. The current through the battery is
1. at t = 0 and at t =
2. at t = 0 and at t =
3. at t = 0 and at t =
4. at t = 0 and at t =
Two conducting circular loops of radii and are placed in the same plane with their centres coinciding. If >>, the mutual inductance M between them will be directly proportional to
1.
2.
3.
4.
The Network shown in the figure is a part of the circuit. (The battery has negligible resistance)
At a certain instant the current I = 2A and it is decreasing at the rate of As. What is the potential difference between the points B and A ?
1. 8.0 V
2. 8.5 V
3. 10 V
4. 15 V
An inductor (L = 100 mH), a resistor (R = 100) and a battery (E = 100V) are initially connected in series as shown in the figure. After a long time the battery is disconnected after short circuiting the points A and B. The current in the circuit 1 ms after the short circiut is
1. e A
2. 0.1 A
3. 1 A
4. 1/e A
A simple pendulum with bob of mass m and conducting wire of length L swings under gravity through an angle 2. The earth's magnetic field component in the direction perpendicular to swing is B. maximum potential difference induced across the pendulum is
1. BLsin(gL)
2. BLsin(gL)
3. BLsin(gL)
4. BLsin(gL)
A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at a point P at a distance r from the centre of the circular region
1. Is zero
2. Decreases as
3. Increases as r
4. Decreases as
Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be
(A)
(B)
(C)
1. Maximum in situation (A)
2. Maximum in situation (B)
3. Maximum in situation (C)
4. The same in all situations
The current in a LR circuit bulids up to 3/4 of its steady state value in 4s. The time constant of this circuit is
1.
2.
3.
4.
A conducting rod AC of length 4l is rotated about a point O in a uniform magnetic field directed into the paper into the paper. AO = l and OC = 3l. Then
1.
2.
3.
4.
Fig shows two circular rings of radii a and b (a>b) joined together by wire of negligible resistance. If the arrangements is placed in a time varying magnetic field, and if the resistance per unit length of wire is , then induced current is
1.
2.
3.
4.
A thin semicircular conducting ring of radius R is falling with its plane vertical in a horizontal magnetic induction . At the position MNQ, the speed of the ring is V. Then the potential difference developed across the ring is
1. zero
2. and M is at higher potential
3. RBV and Q is at a higher potential
4. 2 RBV and Q is at higher potential
A rectangular loop circuit has a sliding wire PQ as shown. The loop is placed in a magnetic field B perpendicular to its plane. The resistance of the wire PQ is R. If the wire PQ moves with constant velocity v, then what is the current through the wire PQ ?
1.
2.
3.
4.
A conducting straight wire PQ of length l is fixed along a diamter of non-conducting ring as shown in fig. The ring is given a pure rolling motion on a horizontal surface such that its centre of mass has a velocity c. There exists a uniform horizontal magnetic field B in horizontal direction perpendicular to the plane of ring. The magnitude of induced emf in the wire PQ at the position shown in fig. will be
1. Bvl
2. 2Bvl
3. 3 Bvl/2
4. zero