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10 Question-answer on Wave nature of particle (de-broglie wave)

1.       A proton and alpha particle are accelerated through the same potential difference. The ratio of their de-Broglie wavelength will be:

(a)    1:1

(b)   1:2

(c)    2:1

(d)   2√2:1

Ans: (d)

2.       A particle with rest mass m₀ is moving with speed of light c. the de-Broglie wavelength associated with it will be:

(a)    ∞

(b)   Zero

(c)    M₀c/h

(d)   Hv/m₀c.

Ans: ( b)

3.       The ratio of wavelengths of proton and deuteron accelerated through the same potential difference will be:

(a)    1:2

(b)   2:1

(c)    √2:1

(d)   1:√2

Ans: ( c)

4.       Through what potential difference should an electron be accelerated so that its de-Broglie wavelength becomes 0.5 A

(a)    6022 V

(b)   602.2 V

(c)    60.22 V

(d)   6.022 V

Ans: (b)

5.       If and p are the energy and the momentum of a photon respectively then on increasing the wavelength of photon

(a)    P and E both will decreases

(b)   P and E both will increases

(c)    P will increases and E will decreases

(d)   P will decrease and E will increase

Ans: (a)

6.       If a photon and an electron have same de-Broglie wavelength, then

(a)    Both have same kinetic energies

(b)   Proton has more K.E. than electron

(c)    Electron has more K.E. than proton

(d)   Both have same velocity

Ans: ( c)

7.       An electron and proton are moving with the same speed. Mass of proton = 1836 times mass of electron. The ratio of their de-Broglie wavelengths will be

(a)    1

(b)   1836

(c)    1/1836

(d)   918

Ans: (b)

8.       Dual nature of radiation is shown by

(a)    Diffraction and reflection

(b)   Refraction and diffraction

(c)    Photoelectric effect alone

(d)   Photoelectric effect and diffraction

Ans: (d)

9.       What should be the velocity of an electron so that its momentum becomes equal to that of a photon of wavelength 5200 A?

(a)    700 m/s

(b)   1000 m/s

(c)    1400 m/s

(d)   2800 m/s

Ans: ( c)

10.       Which of the following pairs of phenomena illustrates the particular aspect of wave-particle duality?

(a)    Compton effect and Bragg’s law

(b)   Photoelectric effect and Compton effect

(c)    Compton effect and Pauli’s principle

(d)   Bragg’s law and photoelectric effect.

Ans: ( a, d)