Magnetism And Matter — Physics STD 12 Science — Question

If in Rutherford’s experiment, the number of particles scattered at 90° angle are 28 per min, then number of scattered particles at an angle 60°  and 120°  will be

(a) 112/min, 12.5/min

(b) 100/min, 200/min

(c) 50/min, 12.5/min

(d) 117/min, 25/min

At breakdown voltage, the rate of creation of hole-electron pairs is _____ leading to the _______ in current. 

A circular metal plate of radius R is rotating with a uniform   angular velocity ω with its plane perpendicular to a uniform magnetic field B. Then the emf developed between the centre and the rim of the plate is

(a) πω

(b) ω

(c) πω

(d) ω

Which of the following electromagnetic waves is used in medicine to destroy cancer cells?

Capacitance (in F) of a spherical conductor with radius 1m is

(a) 1.1

(b)

(c) 9 ×

(d)

In a Young's double slit experiment, the central point on the screen is

(a) Bright	(b) Dark
(c) First bright and then dark	(d) First dark and then bright

A radio receiver antenna that is 2 m long is oriented along the direction of the electromagnetic wave and receives a signal of intensity 5 . The maximum instantaneous potential difference across the two ends of the antenna is

(a) 1.23 mV

(b) 1.23 mV

(c) 1.23 V

(d) 12.3 mV

In Young’s double slit experiment, the distance between the two slits is made half, then the fringe width will become

(a) Half

(b) Double

(c) One fourth

(d) Unchanged

When the charged particles move in a combined magnetic and electric field, then the force acting is known as _________.

Neutrino is a particle, which is

(a) Charged and has spin	(b) Charged and has no spin
(c) Charge less and has spin	(d) Charge less and has no spin