Moving Charges and Magnetism

A charge of 4.0 is moving with a velocity of 4.0 106 ms-1 along the positive y axis under a magnetic field B of strength (2 k) T. The force acting on the charge is x i N. The value of x is .

A proton moving with a constant velocity passes through a region of space without any change in its velocity. If E and B represent the electric and magnetic fields respectively, then the region of space may have : Choose the most appropriate answer from the options given below :

1. (A), (B) and (C) only
2. (A), (C) and (D) only
3. (A), (B) and (D) only
4. (B), (C) and (D) only

Two long, straight wires carry equal currents in opposite directions as shown in figure. The separation between the wires is 5.0 cm. The magnitude of the magnetic field at a point P midway between the wires is (Given : 0 = 4 10-7 T m A-1) [figure]

A current of 200 deflects the coil of a moving coil galvanometer through 60 . The current to cause deflection through 10 radian is :

1. 120
2. 180
3. 30
4. 60

The magnetic field at the centre of a wire loop formed by two semicircular wires of radii R1=2 m and R2=4 m, carrying current I=4 A as per figure given below is 10-7 T. The value of is . (Centre O is common for all segments) [figure]