Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

Microscope is an optical instrument which (a) Enlarges the object (b) Increases the visual angle formed by the object at the eye(c) Decreases the visual angle formed by the object at the eye(d) Brings the object nearer 

If two soap bubbles of different radii are connected by a tube:

1. Air flows from bigger bubble to the smaller bubble till the sizes become equal.
2. Air flows from bigger bubble to the smaller bubble till the sizes are interchanged.
3. Air flows from the smaller bubble to the bigger.
4. There lis no flow of air.

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:

What is the C.G.S. unit of charge?

A point charge is kept at the centre of metallic insulated spherical shell. Then:

Assertion  :   The whole charge of a conductor cannot be transferred to another isolated conductor.
Reason     : The total transfer of charge from one to another is not possible.(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.

Assertion  :  The temperature coefficient of resistance is positive for metals and negative for P-type semiconductor. 
Reason     : The effective charge carriers in metals are negatively charged whereas in P-type semiconductor they are positively charged.(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.

Assertion :  The stars twinkle while the planets do not.
Reason    : The stars are much bigger in size than the planets.(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.

The total power content of an AM wave is 900 W. For 100% modulation, the power transmitted by each side band is (a) 50 W(b) 100 W(c) 150 W(d) 200 W