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 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
2. 20
3. 8
4. 5
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?
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 |
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)
1. | Exactly 10 ohm |
2. | Less than 10 ohm |
3. | More than 10 ohm |
4. | We cannot definitely say |
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.
2.
3.
4.
What is the magnetic dipole moment of the given loop?
1. | \({ 5 \over 2} \pi R^2I\) | 2. | \(3 \pi R^2I\) |
3. | \({ 3 \over 2} \pi R^2I\) | 4. | \(5 \pi R^2I\) |
Which of the following graphs correctly represents the variation of magnetic field induction with distance due to a thin wire carrying current?
1. | 2. | ||
3. | 4. |