Magnetism And Matter — Physics STD 12 Science — Question

Which of the following parameters are the same for all hydrogen-like atoms and ions in their ground states?

Which of the following is/are optoelectronic devices?

The mobility of free electron is greater than that of free holes because

(a) The carry negative charge

(b) They are light

(c) They mutually collide less

(d) They require low energy to continue their motion

The ionisation potential of H-atom is 13.6 V. When it is excited from ground state by monochromatic radiations of 970.6  the number of emission lines will be (according to Bohr’s theory)

(a) 10

(b) 8

(c) 6

(d) 4

In the propagation of electromagnetic waves the angle between the direction of propagation and plane of polarisation is

(a) 0o

(b) 45o

(c) 90o

(d) 180o

What is the valence electron in alkali metal?

If the mass of neutron =1.7×10−27kg . Then the de broglie wavelength of neutron of energy 3eV is:

Assuming that the dimmest visible star to the naked eye has a magnitude of about 6. Brightness of planet Venus (magnitude = – 4) w.r.t. this star is

(a) 10,000 times brighter	(b) 2000 times brighter
(c) 15000 times brighter	(d) 4000 times brighter

The wavelength of de-Broglie wave is 2mm, then its momentum is (h = 6.63 × 10^–34 J-s)

(a) 3.315 × 10–28 kg-m/s

(b) 1.66 × 10–28 kg-m/s

(c) 4.97 × 10–28 kg-m/s

(d) 9.9 × 10–28 kg-m/s

When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection.