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'?
1. | 2. | ||
3. | 4. |
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?
1. | 2. | ||
3. | 4. |
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?
1. | 2. | ||
3. | 4. |
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?
\(F ~\)
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 |