Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

(1) The product of a volt and a coulomb is a joule.

(2)  The product of a volt and an ampere is a joule/second.

(3)  The product of volt and watt is horse power.

(4)  Watt-hour can be measured in terms of electron volt.

State if

(a) All four are correct	(b) (1), (2) and (4) are correct
(c) (1) and (3) are correct	(d) (3) and (4) are correct

The number of dry cells, each of e.m.f. 1.5 volt and internal resistance 0.5 ohm that must be joined in series with a resistance of 20 ohm so as to send a current of 0.6 ampere through the circuit is

(a) 2

(b) 8

(c) 10

(d) 12

A galvanometer of resistance 20 W is to be converted into an ammeter of range 1 A.  If a current of 1 mA produces full scale deflection, the shunt required for the purpose is

(a) 0.01 W

(b) 0.05 W

(c) 0.02 W

(d) 0.04 W

The percentage of Sun's total energy which reaches the earth's surface is

(a) 10–7 %

(b) 10–6 %

(c) 10–3 %

(d) 10–2 %

A positive charge is moving vertically upwards. When it enters a region of magnetic field directed towards north, what is the direction of the force on the charge?

In a YDSE bi-chromatic light of wavelengths 400 nm and 560 nm are used. The distance between the slits is 0.1 mm and the distance between the plane of the slits and the screen is 1m. The minimum distance between two successive regions of complete darkness is

(a) 4 mm

(b) 5.6 mm

(c) 14 mm

(d) 28 mm

The magnetic field at a point x on the axis of a small bar magnet is equal to the field at a point y on the equator of the same magnet. The ratio of the distances of x and y from the centre of the magnet is

(a)

(b)

(c)

(d)

X-rays are produced by accelerating electrons by voltage V and let they strike a metal of atomic number Z. The highest frequency of X-rays produced is proportional to

(a) V

(b) Z

(c) (Z – 1)

(d)

When  ampere current is passed in a tangent galvanometer, there is a deflection of 30° in it. The deflection obtained when 3 amperes current is passed, is

(a) 30°

(b) 45°

(c) 60°

(d) 75°

'Z' is not.