As indicated, a long, straight conductor XY carrying a current i₁ is placed antiparallel to a conductor AB of length l carrying a current i₂. How much of a force is acting on AB?

   

1. ${\mu }_0{i}_1{i}_2$

2.  $\frac{{\mu }_0{i}_1{i}_2}{\mathrm{\pi }}$

3. $\frac{{\mu }_0{i}_1{i}_2}{2\mathrm{\pi }}$

4. $2{\mu }_0{i}_1{i}_2$

Two long straight conductors with currents $l_1 and l_2$ are placed along X and Y-axes. The locus of points of zero magnetic induction is

1. A parabola

2. A rectangular hyperbola

3. A straight line

4. An ellipse

Cyclotron frequency does not depend upon

1. Specific charge

2. Speed of revolving particle

3. Magnetic induction

4. Charge

The maximum kinetic energy of an $\alpha -particle$ coming out of a cyclotron accelerator is 20 MeV. The maximum kinetic energy of a proton that can be obtained from this accelerator is 

1. 20 MeV

2. 40 MeV

3. 10 MeV

4. 5 MeV

In a moving coil galvanometer, magnetic fields line by magnet are made

1. Uniform

2. Concentric

3. Helical

4. Radical

A wire abcdef with each side of length L bent as shown and carrying a current I is placed in a uniform magnetic field B parallel to the positive y-direction. What is the magnitude and direction of the force experienced by the wire?

1. BIL along +z-direction

2. BIL along +y-direction

3. BIL along -z-direction

4. BIL along -y-direction

Current sensitivity of a moving coil galvanometer is \(1~\text{rad /A}\) and its resistance is $\mathrm{}$\(5~\Omega\). Its voltage sensitivity is:
1. \(0.2~\text{rad/V}\)
2. \(0.1~\text{rad/V}\)
3. \(1~\text{rad/V}\)
4. \(2~\text{rad/V}\) 

Torque on a current-carrying coil is maximum in a uniform magnetic field, when

1. Plane of the coil makes an angle ${45}^{\circ }$ with the field

2. Plane of the coil is perpendicular to the field

3. Plane of the coil is parallel to the field

4. Plane of the coil makes an angle ${60}^{\circ }$ with the field

In which of the following situations will there be no force?

1. A positive charge projected past a bar magnet

2. A positive charge sent along the axis of a solenoid 

3. Two parallel wires carrying current in the same direction

4. A positive charge projected between the poles of a magnet 

A straight wire of length ${\left(\mathrm{\pi }\right)}^2$ metre is carrying a current of 2 A and the magnetic field due to it is measured at a point distance 1 cm from it. If the wire is to be bent into a circle and is to carry the same current as before, the ratio of the magnetic field at its center to that obtained in the first case would be

1. 1:100

2. 100:1

3. 1:50

4. 50:1