Magnetism And Matter — Physics STD 12 Science — Question

What is the stopping potential when the metal with work function 0.6 eV is illuminated with the light of 2 eV

(a) 2.6 V

(b) 3.6 V

(c) 0.8 V

(d) 1.4 V

The minimum intensity of light to be detected by human eye is  . The number of photons of wavelength  5.6   entering the eye, with pupil area  , per second for vision will be nearly

(a) 100

(b) 200

(c) 300

(d) 400

If the thermionic current density is J and emitter temperature is T then the curve between   and   will be

(a)

(b)

(c)

(d)

For which of the following colour, the magnifying power of a microscope will be maximum

(a) White colour

(b)  Red colour

(c) Violet colour

(d)  Yellow colour

Conductivity of semiconductors:

In which of the following decays the element does not change?

At absolute zero, Si acts as:

Diamagnetic substances are

(a) Feebly attracted by magnets	(b) Strongly attracted by magnets
(c) Feebly repelled by magnets	(d) Strongly repelled by magnets

The propagation constant of a photon of wavelength 6284 A°.