- Ais zero.
- Bincreases from centre to the surface.
- Cdecreases from centre to the surface.
- Dremains constant from centre to the surface.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
A long magnetic needle of length 2L, magnetic moment M and pole strength m units is broken into two pieces at the middle. The magnetic moment and pole strength of each piece will be
|
(a) |
(b) M, |
(c) |
(d) M, m |
A long straight wire carrying current of 30A is placed in an external uniform magnetic field of induction 4 × 10–4 T. The magnetic field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point 2.0 cm away from the wire is
|
(a) 10–4 |
(b) 3 × 10–4 |
(c) 5 × 10–4 |
(d) 6 × 10–4 |
For what value of unknown resistance X, the potential difference between B and D will be zero in the circuit shown in the figure
|
(a) 4 W |
(b) 6 W |
(c) 2 W |
(d) 5 W |
Switch S of the circuit shown in figure. is closed at t = 0. If e denotes the induced

emf in L and i, the current flowing through the circuit at time t, which of the following graphs is correct
|
(a)
|
(b)
|
(c)
|
(d)
|
In
nucleus, there are
|
(a) 138 protons and 88 neutrons |
(b) 138 neutrons and 88 protons |
|
(c) 226 protons and 88 electrons |
(d) 226 neutrons and 138 electrons |
A point source of light is placed at a distance, of 2f from a converging lens of focal length f. The intensity on the other side of the lens is maximum at a distance:
In a coil of area
and 10 turns with a magnetic field directed perpendicular to the plane and is changing at the rate of
gauss/second. The resistance of the coil is 20 ohm. The current in the coil will be
|
(a) 5 amp |
(b) 0.5 amp |
(c) 0.05 amp |
(d) 5 |