In a moving coil galvanometer the deflection $\theta$ of the coil is related to the electric current by the relation

1. $l\propto \tan \theta$

2. $l\propto \cos \theta$

3. $l\propto \theta$

4. $l\propto {\theta }^2$

A half-metre long wire is lying in a plane perpendicular to the magnetic field. A force of 2 kg wt is acting on it in a magnetic field of 0.98 tesla. The current flowing in it will be

1. 400 A 

2. 40 A

3. 4 A

4. 1 A

A cyclotron cannot be used to accelerate 

1. Deutrons 

2. Protons 

3. Neutrons

4. Both (1) & (3)

                
1. \(\mu_{0} i_{1} i_{2}\)
2. \(\dfrac{\mu_{0} i_{1} i_{2}}{\pi}\)
3. \(\dfrac{\mu_{0} i_{1} i_{2}}{2 \pi}\)
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

The 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. \(2~\text{rad/V}\)