Assertion : Radioactive nuclei emit 
particles.
Reason : Electrons exist inside the nucleus.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
(c) If assertion is true but reason is false.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
When the temperature of silicon sample is increased from 27℃ to 100℃, the conductivity of silicon will be
|
(a) Increased |
(b) Decreased |
(c) Remain same |
(d) Zero |
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 |
Huygen's conception of secondary waves
|
(a) Allow us to find the focal length of a thick lens |
|
(b) Is a geometrical method to find a wavefront |
|
(c) Is used to determine the velocity of light |
|
(d) Is used to explain polarisation |
In a step-up transformer the turn ratio is 1:10. A resistance of 200 ohm connected across the secondary is drawing a current of 0.5 A. What is the primary voltage and current
|
(a) 50 V, 1 amp |
(b) 10 V, 5 amp |
(c) 25 V, 4 amp |
(d) 20 V, 2 amp |
The power rating of an electric motor which draws a current of 3.75 amperes when operated at 200 V is about
|
(a) 1 H.P. |
(b) 500 W |
(c) 54 W |
(d) 750 H.P. |
There is a current of 20 amperes in a copper wire of 
square metre area of cross-section. If the number of free electrons per cubic metre is 
, then the drift velocity is
|
(a) 125 |
(b) 12.5 |
(c) 1.25 |
(d) 1.25 |
At what distance from a convex lens of focal length 30 cm, an object should be placed so that the size of the image be 1/2 of the object
|
(a) 30 cm |
(b) 60 cm |
(c) 15 cm |
(d) 90 cm |
