- ✓attract each other
- Brepel each other
- Cnot exert any force on each other
- Dcurrent in one of the wire vanishes
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A biconvex lens with equal radii curvature has refractive index 1.6 and focal length 10 cm. Its radius of curvature will be
|
(a) 20 cm |
(b) 16 cm |
(c) 10 cm |
(d) 12 cm |
Two identical circular loops of metal wire are lying on a table without touching each other. Loop-A carries a current which increases with time. In response, the loop-B
|
(a) Remains stationary |
|
(b) Is attracted by the loop-A |
|
(c) Is repelled by the loop-A |
|
(d) Rotates about its CM, with CM fixed |
The magnetic field at a distance r from a long wire carrying current i is 0.4 Tesla. The magnetic field at a distance 2r is
|
(a) 0.2 Tesla |
(b) 0.8 Tesla |
(c) 0.1 Tesla |
(d) 1.6 Tesla |
A circular coil ‘A’ has a radius R and the current flowing through it is I. Another circular coil ‘B’ has a radius 2R and if 2I is the current flowing through it, then the magnetic fields at the centre of the circular coil are in the ratio of (i.e. to
)
|
(a) 4 : 1 |
(b) 2 : 1 |
(c) 3 : 1 |
(d) 1 : 1 |
If the operating potential of an X-ray tube is 50 kV, the velocity of X-rays coming out of it is
|
(a) 4 |
(b) 3 |
(c) |
(d) 3 m/s |