A circular loop with a radius of 20 cm is placed in a uniform magnetic field B = 2T in the XY plane as shown in the figure. If the loop carries a current of i = 1 A, then the magnitude of torque acting on the loop will be:
       
1.  0.25 N-m

2.  5.2 N-m

3.  2.5 N-m

4.  0.52 N-m

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?

If an electron of velocity $\left(2\hat{\mathrm{i}}\right)$ $+$ $3\hat{j}$ is subjected to a magnetic field of \(4\hat{\mathrm{k}}\) :

When a 12 Ω resistor is connected in parallel with a moving coil galvanometer, its deflection reduces from 50 divisions to 10 divisions. What will be the resistance of the galvanometer?

1. 24 Ω

2. 36 Ω

3. 48 Ω

4. 60 Ω

If an ammeter A reads 2 A and the voltmeter V reads 20 V, what is the value of resistance R? (Assuming finite resistances of ammeter and voltmeter)
     

A galvanometer with a resistance of 36 Ω is changed into an ammeter by using a shunt of 4 Ω. The fraction f0 of total current passing through the galvanometer will be:

1. $\frac{1}{40}$

2. $\frac{1}{4}$

3. $\frac{1}{140}$ 

4. $\frac{1}{10}$

A galvanometer of resistance 240 Ω allows only 4% of the main current after connecting a shunt resistance. What is the value of shunt resistance?

1.  10 $\mathrm{\Omega }$

2.  20 $\mathrm{\Omega }$

3.  8 $\mathrm{\Omega }$

4.  5 $\mathrm{\Omega }$

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?

What is the magnetic dipole moment of the given loop?

A positively charged particle descends vertically. In which direction will the horizontal component of the earth's magnetic field deflect?

1. east

2. west

3. north

4. south