Q. No.A rectangular loop carrying a current \(I_1,\) is situated near a long straight wire carrying a steady current \(I_2.\) If the wire is parallel to one of the sides of the loop and is in the plane of the loop as shown in the figure, then the current loop will:
1. move away from the wire.
2. move towards the wire.
3. remain stationary.
4. rotate about an axis parallel to the wire.
1. move away from the wire.
2. move towards the wire.
3. remain stationary.
4. rotate about an axis parallel to the wire.
(\(N=\) number of turns, \(B=\) magnetic field, \(A=\) area of coil, and \(C=\) Torsional constant of spring)
| 1. | \(N\) is small | 2. | \(B\) is small |
| 3. | \(A\) is small | 4. | \(C\) is small |
Two toroids \(1\) and \(2\) have total no. of turns \(200\) and \(100\) respectively with average radii \(40~\text{cm}\) and \(20~\text{cm}\) respectively. If they carry the same current \(i,\) what will be the ratio of the magnetic fields along the two loops?
1. \(1:1\)
2. \(4:1\)
3. \(2:1\)
4. \(1:2\)
A beam of electrons passes un-deflected through mutually perpendicular electric and magnetic fields. Where do the electrons move if the electric field is switched off and the same magnetic field is maintained?
| 1. | in an elliptical orbit. |
| 2. | in a circular orbit. |
| 3. | along a parabolic path. |
| 4. | along a straight line. |
A particle of mass \(m,\) charge \(Q,\) and kinetic energy \(T\) enters a transverse uniform magnetic field of induction \(\vec B.\) What will be the kinetic energy of the particle after seconds?
| 1. | \(3{T}\) | 2. | \(2{T}\) |
| 3. | \({T}\) | 4. | \(4{T}\) |
A closed-loop \(PQRS\) carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments \(PS,\) \(SR,\) and \(RQ\) are \(F_1, F_2~\text{and}~F_3\) respectively, and are in the plane of the paper and along the directions shown, then which of the following forces acts on the segment \(QP?\)
1. \(F_{3} - F_{1} - F_{2}\)
2. \(\sqrt{\left(F_{3} - F_{1}\right)^{2} + F_{2}^{2}}\)
3. \(\sqrt{\left(F_{3} - F_{1}\right)^{2} - F_{2}^{2}}\)
4. \(F_{3} - F_{1} + F_{2}\)
| a. | \(\vec{B}\) should be perpendicular to the direction of velocity and \(\vec{E}\) should be along the direction of velocity. |
| b. | Both \(\vec{B}\) and \(\vec{E}\) should be along the direction of velocity. |
| c. | Both \(\vec{B}\) and \(\vec{E}\) are mutually perpendicular and perpendicular to the direction of velocity. |
| d. | \(\vec{B}\) should be along the direction of velocity and \(\vec{E}\) should be perpendicular to the direction of velocity. |
Which one of the following pairs of statements are possible?
1. (a) and (c)
2. (c) and (d)
3. (b) and (c)
4. (b) and (d)
| 1. | \(8\) N in \(-z\text-\)direction. |
| 2. | \(4\) N in the \(z\text-\)direction. |
| 3. | \(8\) N in the \(y\text-\)direction. |
| 4. | \(8\) N in the \(z\text-\)direction. |
Two particles each of mass \(m\) and charge \(q\) are attached to the two ends of a light rigid rod of length \(2R\). The rod is rotated at constant angular speed about a perpendicular axis passing through its centre.
What is the ratio of the magnitudes of the magnetic moment of the system and its angular momentum about the centre of the rod?
1. \(\frac{q}{2m}\)
2. \(\frac{q}{m}\)
3. \(\frac{2q}{m}\)
4. \(\frac{q}{\pi m}\)
| 1. | \(3 \overrightarrow{F}\) | 2. | \(- \overrightarrow{F}\) |
| 3. | \(-3 \overrightarrow{F}\) | 4. | \( \overrightarrow{F}\) |
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