Focal length of a plane mirror is
|
(a) Zero |
(b) Infinite |
(c) Very less |
(d) Indefinite |
Focal length of a plane mirror is
|
(a) Zero |
(b) Infinite |
(c) Very less |
(d) Indefinite |
(b) Infinite
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
The S.I. unit of magnetic permeability is
|
(a) |
(b) Am |
|
(c) |
(d) No unit, it is a dimensionless number |

5 amperes of current is passed through a metallic conductor. The charge flowing in one minute in coulombs will be
|
(a) 5 |
(b) 12 |
(c) 1/12 |
(d) 300 |
A 4 mF capacitor, a resistance of 2.5 MW is in series with 12 V battery. Find the time after which the potential difference across the capacitor is 3 times the potential difference across the resistor. [Given ln(2)= 0.693]
|
(a) 13.86 s |
(b) 6.93 s |
(c) 7 s |
(d) 14 s |
A magnetic needle suspended by a silk thread is vibrating in the earth's magnetic field. If the temperature of the needle is increased by 500°C, then
| (a) The time period decreases | (b) The time period remains unchanged |
| (c) The time period increases | (d) The needle stops vibrating |
X-rays are not used for radar purpose because
| (a) They are not reflected by the target |
| (b) They are not electromagnetic waves |
| (c) They are completely absorbed by the air |
| (d) They sometimes damage the target |