Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

The ratio of specific charge of an α -particle to that of a proton is

(a) 2 : 1

(b) 1 : 1

(c) 1 : 2

(d) 1 : 3

The force of attraction or repulsion between two charges is given by __________.

Two capacitances of capacity  and  are connected in series and potential difference V is applied across it. Then the potential difference across  will be

(a)

(b)

(c)

(d)

The excess pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n is:

1. 4
2. 2
3. 1
4. 0.125.

The nuclei having same number of protons but different number of neutrons are called _________.

Assertion :   Gauss theorem is not applicable in magnetism.

Reason    : Mono magnetic pole does not exist.

(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.

Two parallel slits 0.6 mm apart are illuminated by light source of wavelength 6000 Å. The distance between two consecutive dark fringes on a screen 1 m away from the slits is

(a) 1 mm

(b) 0.01 mm

(c) 0.1 m

(d) 10 m

Visible light passing through a circular hole forms a diffraction disc of radius 0.1mm on a screen. If an X-ray is passed through the same setup, the radius of the diffraction disc will be:

1. zero
2. < 0.1mm
3. 0.1mm
4. > 0.1m

The two ends of a uniform conductor are joined to a cell of e.m.f. E and some internal resistance. Starting from the midpoint P of the conductor, we move in the direction of current and return to P. The potential V at every point on the path is plotted against the distance covered (x). Which of the following graphs best represents the resulting curve

(a)

(b)

(c)

(d)