Nuclei — Physics STD 12 Science — Question

Gauss’s law is true only if force due to a charge varies as:

A metallic resistor is connected across a battery. If the number of collisions of the free electrons with the lattice is somehow decreased in the resistor (for example, by cooling it), the current will:

Semiconductors are generally made up of which substance?

Consider the following two statements A and B and identify the correct choice given in the answers

(A) Duddells thermo-galvanometer is suitable to measure direct current only

(B) Thermopile can measure temperature differences of the order of

(a) Both A and B are true	(b) Both A and B are false
(c) A is true but B is false	(d) A is false but B is true

For sky wave propagation of a 10 MHz signal, what should be the minimum electron density in ionosphere

(a) ~ 1.2 × 1012 m–3

(b) ~ 106 m–3

(c) ~ 1014 m–3

(d) ~ 1022 m–3

The value of amplification factor from the following graph will be

(a) 10

(b) 50

(c) 25

(d) 40

An electric charge in uniform motion produces:

The graph between intensity of light falling on a metallic plate (I) with the current (i) generated is

(a)

(b)

(c)

(d)

Which one of the following graphs in following figure represents variation of reactance ′X_c′​ of a capacitor with frequency 'f' of an ac supply?

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%