Q. No.
Which among the following options needs to be decreased to increase the sensitivity of a moving coil galvanometer?
1.
the number of turns in the coil.
2.
the area of the coil.
3.
the magnetic field.
4.
the couple per unit twist of the suspension.
In a hydrogen atom, the electron makes 6.6×1015 rev/sec around the nucleus in an orbit of radius 0.528 Å. What will (A-m2) its magnetic moment be?
1.
2.
3.
4.
What is a representation of the magnetic field caused by a straight conductor with a uniform cross-section and a steady current of radius 'a'?
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A particle of charge q and mass m is moving along the x-axis with a velocity of v and enters a region of electric field E and magnetic field B as shown in the figure below. For which figure is the net force on the charge zero?
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A current-carrying wire is placed in a uniform magnetic field in the shape of the curve \(y= \alpha sin ({\pi x \over L}),~0 \underline{<}x \underline{<}~2L\)
. What will be the force acting on the wire?
| 1. | \(iBL \over \pi\) | 2. | \(iBL \pi\) |
| 3. | \(2iBL \) | 4. | Zero |
A circular coil is in the y-z plane with its centre at the origin. The coil carries a constant current. Assuming the direction of the magnetic field at x = – 25 cm to be positive, which of the following graphs shows the variation of the magnetic field along the x-axis?
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A particle of charge +q and mass m moving under the influence of a uniform electric field and a uniform magnetic field follows a trajectory from P to Q as shown in the figure. The velocities at P and Q are and respectively. Which of the following statement(s) is/are correct?
| 1. | \(\mathrm{E}=\frac{3}{4} \frac{\mathrm{mv}^2}{\mathrm{qa}}\) |
| 2. | Rate of work done by electric field at P is\(\frac{3}{4} \frac{\mathrm{mv}^3}{\mathrm{a}}\) |
| 3. | Rate of work done by both fields at Q is zero |
| 4. | All of the above |
A particle with charge q, moving with a momentum p, enters a uniform magnetic field normally. The magnetic field has magnitude B and is confined to a region of width d, where . The particle is deflected by an angle in crossing the field, then:
| 1. | \(\sin \theta={Bqd \over p}\) | 2. | \(\sin \theta={p \over Bqd}\) |
| 3. | \(\sin \theta={Bp \over qd}\) | 4. | \(\sin \theta={pd \over Bq}\) |
A current I is carried by an elastic circular wire of length L. It is placed in a uniform magnetic field B (out of paper) with its plane perpendicular to B's direction. What will happen to the wire?
| 1. | No force | 2. | A stretching force |
| 3. | A compressive force | 4. | A torque |
What will happen if two thin, long parallel wires separated by a distance "d" carry current "i" in the same direction?
| 1. | attract each other with a force per unit length of |
| 2. | repel each other with a force per unit length of |
| 3. | attract each other with a force per unit length of |
| 4. | repel each other with a force per unit length of |
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