Semiconductor Electronics: Materials, Devices and Simple Circuits — Physics STD 12 Science — Question

A silver voltameter of resistance 2 ohm and a 3 ohm resistor are connected in series across a cell. If a resistance of 2 ohm is connected in parallel with the voltameter, then the rate of deposition of silver

(a) Decreases by 25%	(b) Increases by 25%
(c) Increases by 37.5%	(d) Decreases by 37.5%

A capacitor acts as an infinite resistance for.

A square coil   area is placed perpendicular to a uniform magnetic field of intensity . The magnetic flux through the coil is

(a) 10 weber

(b)  weber

(c)  weber

(d) 100 weber

What name is given to a cylindrical coil of diameter less than its length?

The S.I. unit of electric flux is:

A man runs towards mirror at a speed of 15 m/s. What is the speed of his image

(a) 7.5 m/s

(b) 15 m/s

(c) 30 m/s

(d) 45 m/s

A magnetic needle suspended horizontally by an unspun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from

(a) The torsion of the silk fibre

(b) The force of gravity

(c) The horizontal component of earth's magnetic field

(d) All the above factors

A capacitor of capacity C is connected with a battery of potential V in parallel. The distance between its plates is reduced to half at once, assuming that the charge remains the same. Then to charge the capacitance upto the potential V again, the energy given by the battery will be

(a)

(b)

(c)

(d)

The ratio of magnetic fields due to a smaller bar magnet in the end on position to broad side on position is:

Two metal plates having charges Q, -Q face each other at some separation and are dipped into an oil tank. If the oil is pumped out, the electric field between the plates will:

1. Increase.
2. Decrease.
3. Remain the same.
4. Become zero.