A vertical wire kept in Z-X plane carries a current from Q to P (see figure). The magnetic field due to current-carrying wire will have the direction at the origin O along :

1. OX

2. OX'

3. OY

4. OY'

                                                                           

In a current-carrying long solenoid, the field produced does not depend upon:

For the magnetic field to be maximum due to a small element of current-carrying conductor at a point, the angle between the element and the line joining the element to the given point must be:

1. 0°                           
2. 90°
3. 180°                        
4. 45°

An electron and a proton with equal momentum enter perpendicularly into a uniform magnetic field, then :

Cyclotron cannot be used to accelerate

1. Electrons                       

2. Neutrons

3. Positive ions                   

4. Both (1) and (2)

 The dimension of the magnetic field intensity B is:

1.  ${\mathrm{MLT}}^{-2}{\mathrm{A}}^{-1}$                   

2.  ${\mathrm{MT}}^{-2}{\mathrm{A}}^{-1}$

3.  ${\mathrm{ML}}^2{\mathrm{TA}}^{-2}$                       

4.  ${\mathrm{M}}^2{\mathrm{LT}}^{-2}{\mathrm{A}}^{-1}$

An $\mathrm{\alpha }-$ particle travels in a circular path of radius 0.45 m in a magnetic field $\mathrm{B}=1.2 Wb\mathit{/}{m}^{\mathit{2}}$ with a speed of $2.6\times {10}^7 m\mathit{/}sec$ . The period of revolution of the $\mathrm{\alpha }-$ particle is :

1.  $1.1\times {10}^{-5 }$ sec          2.  $1.1\times {10}^{-6}$ sec

3.  $1.1\times {10}^{-7}$ sec            4.  $1.1\times {10}^{-8}$ sec

A rectangular loop carrying a current i is situated near a long straight wire such that the wire is parallel to the one of the sides of the loop and is in the plane of the loop. If a steady current I is established in wire as shown in figure, the loop will

1. Rotate about an axis parallel to the wire

2. Move away from the wire or towards right

3. Move towards the wire

4. Remain stationary

To make the field radial in a moving coil galvanometer :

1. The number of turns in the coil is increased

2. Magnet is taken in the form of horse-shoe

3. Poles are cylindrically cut

4. The coil is wounded on the aluminum frame