Some Mechanical Properties of Matter — Physics STD 12 Science — Question

The angular momentum of electron in n^th orbit is given by

(a) nh

(b)

(c) n

(d)

A point object is placed at a distance of 10 cm  and its real image is formed at a distance of 20 cm from a concave mirror. If the object is moved by 0.1 cm towards the mirror, the image will shift by about

(a) 0.4 cm away from the mirror	(b) 0.4 cm towards the mirror
(c) 0.8 cm away from the mirror	(d) 0.8 cm towards the mirror

Dielectric constant for metal is

(a) Zero

(b) Infinite

(c) 1

(d) Greater than 1

Source of Sun's energy is

(a) Burning of hydrogen	(b) Fission reactions involving hydrogen
(c) Fusion reactions involving hydrogen	(d) Some other source

Which of the following are not electromagnetic waves

(a) Cosmic rays

(b) Gamma rays

(c) b-rays

(d) X-rays

Which of the following defines electromagnetic induction:

A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866u. The energy liberated per u is (Given 1 u = 931MeV)

The stopping potential as a function of the frequency of the incident radiation is plotted for two different photoelectric surfaces A and B. The graphs show that work function of A is

(a) Greater than that of B

(b) Smaller than that of B

(c) Equal to that of B

(d) No inference can be drawn about their work functions from the given graphs

A thin oil layer floats on water. A ray of light making an angle of incidence of 40° shines on oil layer. The angle of refraction of light ray in water  is ()

(a) 36 .1°

(b) 44.5°

(c) 26. 8°

(d) 28.9°

The electric potential at the surface of an atomic nucleus (Z = 50) of radius 9.0 ×   cm is

(a) 80 volts

(b) 8  volts

(c) 9 volts

(d) 9  volts