1. | \({G \over (S+G)}\) | 2. | \({S^2 \over (S+G)}\) |
3. | \({SG \over (S+G)}\) | 4. | \({G^2 \over (S+G)}\) |
Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency of f Hz. The magnitude of magnetic induction at the centre of the ring is:
1.
2.
3.
4.
A square loop, carrying a steady current I, is placed in a horizontal plane near a long straight conductor carrying a steady current I1 at a distance d from the conductor as shown in the figure. The loop will experience:
1. | a net attractive force towards the conductor |
2. | a net repulsive force away from the conductor |
3. | a net torque acting upward perpendicular to the horizontal plane |
4. | a net torque acting downward normal to the horizontal plane |
A current loop consists of two identical semicircular parts each of radius R, one lying in the x-y plane and the other in x-z plane. If the current in the loop is I, then the resultant magnetic field due to the two semicircular parts at their common centre is:
1.
2.
3.
4.
A particle having a mass of \(10^{-2}\) kg carries a charge of \(5\times 10^{-8}~\mathrm{C}\). The particle is given an initial horizontal velocity of \(10^5~\mathrm{ms^{-1}}\) in the presence of electric field \(\vec{E}\) and magnetic field \(\vec{B}\) . To keep the particle moving in a horizontal direction, it is necessary that:
(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 is possible?
1. | (c) and (d) |
2. | (b) and (c) |
3. | (b) and (d) |
4. | (a) and (c) |
A proton carrying \(1~\text{MeV}\) kinetic energy is moving in a circular path of radius \(R\) in a uniform magnetic field. What should be the energy of an \(\alpha \text- \)particle to describe a circle of the same radius in the same field?
1. \(1~\text{MeV}\)
2. \(0.5~\text{MeV}\)
3. \(4~\text{MeV}\)
4. \(2~\text{MeV}\)
A coil of one loop is made from a wire of length L and thereafter a coil of two loops is made from same wire. The ratio of magnetic field at the centre of the coils will be:
1. 1 : 4
2. 1 : 1
3. 1 : 8
4. 4 : 1
For the adjoining figure, the magnetic field at a point 'P' will be:
1.
2.
3.
4.
A charge having q/m equal to 108 c/kg and with velocity 3 × 105 m/s enters into a uniform magnetic field B = 0.3 tesla at an angle 30º with the direction of field. Then the radius of curvature will be:
1. 0.01 cm
2. 0.5 cm
3. 1 cm
4. 2 cm