At two places A and B using vibration magnetometer, a magnet vibrates in a horizontal plane and its respective periodic time are 2 sec and 3 sec and at these places the earth's horizontal components are HA and HB respectively. Then the ratio between HA and HB will be
| (a) 9 : 4 | (b) 3 : 2 | (c) 4 : 9 | (d) 2 : 3 |
(a) 9 : 4
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
If potential V = 100 ± 0.5 Volt and current I = 10 ± 0.2 amp are given to us. Then what will be the value of resistance
|
(a) 10 ± 0.7 ohm |
(b) 5 ± 2 ohm |
(c) 0.1 ± 0.2 ohm |
(d) None of these |
The current in a coil of inductance 5 H decreases at the rate of 2 A/s. The induced e.m.f. is
|
(a) 2 V |
(b) 5 V |
(c) 10 V |
(d) – 10 V |
A concave lens and a convex lens have same focal length of 20 cm and both put in contact this combination is used to view an object 5 cm long kept at 20 cm from the lens combination. As compared to object the image will be
|
(a) Magnified and inverted |
(b) Reduced and erect |
|
(c) Of the same size and erect |
(d) Of the same size and inverted |
When a certain circuit consisting of a constant e.m.f. E an inductance L and a resistance R is closed, the current in, it increases with time according to curve 1. After one parameter (E, L or R) is changed, the increase in current follows curve 2 when the circuit is closed second time. Which parameter was changed and in what direction
|
(a) L is increased |
(b) L is decreased |
(c) R is increased |
(d) R is decreased |
If a hole is made at the centre of a bar magnet, then its magnetic moment will
| (a) Increase | (b) Decrease | (c) Not change | (d) None of these |