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. | \(4{T}\) |
What is the result of an electric charge in uniform motion?
| 1. | an electric field only. |
| 2. | a magnetic field only. |
| 3. | both electric and magnetic field. |
| 4. | neither electric nor magnetic field. |
A particle of charge \(+q\) and mass \(m\) moving under the influence of a uniform electric field \(E\hat i\) and a uniform magnetic field \(\mathrm B\hat k\) follows a trajectory from \(P\) to \(Q\) as shown in the figure. The velocities at \(P\) and \(Q\) are \(v\hat i\) and \(-2v\hat j\) respectively. Which of the following statement(s) is/are correct?
| 1. | \(E=\frac{3}{4} \frac{{mv}^2}{{qa}}\). |
| 2. | Rate of work done by electric field at \(P\) is \(\frac{3}{4} \frac{{mv}^3}{a}\). |
| 3. | Rate of work done by both fields at \(Q\) is zero. |
| 4. | All of the above. |
| 1. | kinetic energy changes |
| 2. | kinetic energy remains constant |
| 3. | speed changes |
| 4. | momentum remains constant |
Moving perpendicular to field \(B\), a proton and an alpha particle both enter an area of uniform magnetic field \(B\). If the kinetic energy of the proton is \(1~\text{MeV}\) and the radius of the circular orbits for both particles is equal, the energy of the alpha particle will be:
1. \(4~\text{MeV}\)
2. \(0.5~\text{MeV}\)
3. \(1.5~\text{MeV}\)
4. \(1~\text{MeV}\)
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. |
| 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. |
A current-carrying wire is placed in a uniform magnetic field in the shape of the curve \(y= \alpha \sin \left({\pi x \over L}\right),~0 \le x \le2L.\)
What will be the force acting on the wire?

| 1. | \(iBL \over \pi\) | 2. | \(iBL \pi\) |
| 3. | \(2iBL \) | 4. | zero |
| 1. | \(1~\text{GHz}\) | 2. | \(100~\text{MHz}\) |
| 3. | \(62.8~\text{MHz}\) | 4. | \(6.28~\text{MHz}\) |
| Statement I: | The electric force changes the speed of the charged particle and hence changes its kinetic energy: whereas the magnetic force does not change the kinetic energy of the charged particle. |
| Statement II: | The electric force accelerates the positively charged particle perpendicular to the direction of the electric field. The magnetic force accelerates the moving charged particle along the direction of the magnetic field. |
| 1. | Both Statement I and Statement II are correct. |
| 2. | Both Statement I and Statement II are incorrect. |
| 3. | Statement I is correct and Statement II is incorrect. |
| 4. | Statement I is incorrect and Statement II is correct. |