Page 1 - worksheet-2 on Dual Nature of light

Worksheet-2

Dual nature of light

1 A proton, a neutron, an electron and an a-particle have same energy. Then their de
Broglie wavelengths compare as [NCERT Exemplar]
(a)λp = λn > λe > λα
(b) λα < λp = λn < λe
(‘C) λe < λp = λn > λα
(d) λe = λp = λn = λα
2 An electron is moving with an initial velocity v = v0i and is in a magnetic field B = B0 j.
Then, its de Broglie wavelength [NCERT Exemplar]
(a) remains constant.
(b) increases with time.
(c) decreases with time.
(d) increases and decreases periodically.
3 The minimum energy required for the electron emission from the metal surface can be
supplied to the free electrons by which of the following physical processes?
(a) Thermionic emission
(b) Field emission
(c) Photoelectric emission
(d) All of these
4 A metal surface ejects electrons when hit by green light but nothing when hit by yellow
light. The electrons will be ejected when the surface is hit by
(a) blue light
(b) heat rays
(c) infrared light
(d) red light
5 The figure shows stopping V0A potential V0 and frequency o for two different metallic
surfaces A and B. The work function of A, as compared to that of B is

(a) less
(b) more
(c) equal
(d) nothing can be said
6 The figure shows the variation of photocurrent with anode potential for a photosensitive
surface for three different radiations. Let Ia, Ib and Ic be the intensities and va, vb. and
vcbe the frequencies for the curves a, b and c respectively. Then the correct relation is