When an electron enters perpendicularly in a magnetic field with velocity v, time period of its revolution is T. If it enters in the same magnetic field with a velocity 2v, then its time period will be:
1. 2T
2. 4T
3.
4. T
An electron is traveling along the x-direction. It encounters a magnetic field in the y-direction. Its subsequent motion will be:
1. Straight-line along the x-direction
2. A circle in the xz-plane
3. A circle in the yz-plane
4. A circle in the xy-plane
A closed-loop (of any shape) carrying current lies in the x-y plane. What happens when a uniform magnetic field B is present in the region such that the loop experiences zero force?
1. | B acts along the x-axis |
2. | B acts along the y-axis |
3. | B acts along the z-axis |
4. | B can act along any of the above direction for the net force to be zero |
A circular coil of wire of radius 'r' has 'n' turns and carries a current 'I'. The magnetic induction (B) at a point on the axis of the coil at a distance from its center is :
1.
2.
3.
4.
The dots in the figure depict a magnetic field that is perpendicular to the plane of the paper and emanates from it. The trajectory of a particle in the plane of the paper is depicted by the curve ABC. What exactly is the particle?
1. | Proton. | 2. | Electron. |
3. | Neutron. | 4. | It cannot be predicted. |
If an electron of velocity is subjected to a magnetic field of \(4\hat{\mathrm{k}}\) :
1. | the speed will change. |
2. | the direction will change. |
3. | both (1) and (2) |
4. | none of the above |
The magnetic induction at point P, which is 4 cm from a long current-carrying wire is 10-8 Tesla. What would be the field of induction at a distance of 12 cm from the same current?
1. | 3.33 x 10-9 Tesla |
2. | 1.11 x 10-4 Tesla |
3. | 3 x 10-3 Tesla |
4. | 9 x 10-2 Tesla |
Two straight horizontal parallel wires carry the same current in the same direction, and d is the distance between them. You are given a small magnetic needle that is freely suspended. Which of the following positions will have the needle's orientation independent of the magnitude of the current in the wires?
1. | At a distance d/2 from any of the wires in any plane. |
2. | At a distance d/3 from any of the wires in the horizontal plane. |
3. | Anywhere on the circumference of a vertical circle of radius d and centre halfway between the wires. |
4. | At points halfway between the wires in the horizontal plane. |
In the figure shown, the magnetic induction at the centre of the arc due to the current in portion AB will be
(a) (c)
(b) (d) Zero
In a current-carrying long solenoid, the field produced does not depend upon:
1. | Number of turns per unit length | 2. | Current flowing |
3. | Radius of the solenoid | 4. | All of the above |