MODEL PAPER 8 — Physics STD 12 Science — Question

In a copper voltameter experiment, current is decreased to one-fourth of the initial value but it is passed for four times the earlier duration. Amount of copper deposited will be

(a) Same	(b) One-fourth the previous value
(c) Four times the previous value	(d)  of the previous value

The angular speed of the electron in the nth orbit of Bohr hydrogen atom is?

If resistance of voltmeter is 10000 W and resistance of ammeter is 2 W then find R when voltmeter reads 12V and ammeter reads 0.1 A

(a) 118 W

(b) 120 W

(c) 124 W

(d) 114W

The X-ray beam emerging from an X-ray tube:

A player with 3 m long iron rod runs towards east with a speed of 30 km/hr. Horizontal component of earth's magnetic field is 4 . If he is running with rod in horizontal and vertical positions, then the potential difference induced between the two ends of the rod in two cases will be

(a) Zero in vertical position and 1  in horizontal position

(b) 1  in vertical position and zero is horizontal position

(c) Zero in both cases

(d) 1  in both cases

When the momentum of a proton is changed by an amount P₀, the corresponding change in the de-Broglie wavelength is found to be 0.25%. Then, the original momentum of the proton was

(a) p0

(b) 100 p0

(c) 400 p0

(d) 4 p0

Nucleus produced due to a-decay of the nucleus   is

(a)

(b)

(c)

(d)

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

Number of spectral lines in hydrogen atom is    

(a) 3

(b) 6

(c) 15

(d) Infinite

What is the atomic mass (u) of sodium?