1.
The Compton shift Δλ is twice the Compton wavelength if the scattering angle is
A. 
B. 
C. 
D. 
2.
According to Rayleigh-Jeans' radiation law, the emissive power of a blackbody over a wavelength range λ to λ+dλ is proportional to λⁿ. Then n is
A. 
B. 
C. 
D. 
3.
The rest mass of a photon of frequency ν is
A. 
B. 
C. 
D. 
4.
What is the speed of a particle whose mass is 3 times its rest mass?
A. 
B. 
C. 
D. 
5.
In Compton scattering, if the angle of scattering varies from 0º to 180º, the electron's recoil angle varies from
A. 
B. 
C. 
D. 
6.
The radiated intensity per unit time from a cavity kept at temperature 1000 Kelvin is 5.67x10ⁿ W/m². The value of n is
A. 
B. 
C. 
D. 
7.
The de Broglie wavelength of an electron accelerated by a potential of 150 V is
A. 
B. 
C. 
D. 
8.
The momentum of an electron (rest mass energy = 0.5 MeV) is 1 MeV/c. Its energy in MeV is
A. 
B. 
C. 
D. 
9.
The de Broglie wavelength of a thermal neutron of mass m at temperature T is given by λ =
A. 
B. 
C. 
D. 
10.
In Davisson-Germer's experiment the highest peak was obtained at an angle θ = 50° with a voltage of 54 V. The de Broglie wavelength of electrons was
A. 
B. 
C. 
D. 
11.
A proton accelerated through a potential difference of V has the same de Broglie wavelength as an α-particle subjected to a potential difference of
A. 
B. 
C. 
D. 
12.
GaP, a semiconductor with an energy gap of 2.25 eV, is used to make LEDs. The wavelength of emitted light from pure GaP is
A. 
B. 
C. 
D. 
13.
The peak wavelengths of radiation of a red-hot and a yellow-hot object are 630 nm and 570 nm respectively. If the red-hot object's temperature is 5000 K, the other's temperature is
A. 
B. 
C. 
D. 
14.
In relation to Rayleigh-Jeans law, the ultraviolet catastrophe refers to the prediction
A. 
B. 
C. 
D. 
15.
According to Planck, the average energy of cavity oscillators in the frequency range ν to ν+dν is given by
A. 
B. 
C. 
D. 
16.
The energy of photons contained in visible light of wavelength 600 nm is
A. 
B. 
C. 
D. 
17.
If visible light is used in Compton scattering the Compton shift will be
A. 
B. 
C. 
More positive than what is observed with X-rays
D. 
Positive but not detectable in the visible window
18.
The number of oscillation modes per unit volume for em standing waves of frequency ν in a blackbody cavity is proportional to
A. 
B. 
C. 
D. 
19.
The Compton shift Δλ is half the Compton wavelength if the scattering angle is
A. 
B. 
C. 
D. 
20.
Compton scattering is performed on blocks of carbon and silver. If I and I' are the intensities of the unmodified (λ) and Compton-shifted (λ') lines in the scattered X-rays, then
A. 
I > I' for both carbon and silver
B. 
I = I' for both carbon and silver
C. 
I > I' for carbon, I < I' for silver
D. 
I < I' for carbon, I > I' for silver
21.
For cavity radiation of wavelength λ at absolute temperature T, Wien's radiation law corresponds to Planck's law when
A. 
B. 
C. 
D. 
Photon's energy has any finite value
22.
If one measures the energy of a photon accurately the uncertainty in the measurement of frequency becomes
A. 
B. 
C. 
D. 
23.
If the measured momentum of an electron is 3.20 x10ˉ²⁷ kg-m/s with an uncertainty of 1.6 x10ˉ²⁹ kg-m/s, what is the minimum uncertainty in the determination of its position?
A. 
B. 
C. 
D. 
24.
The Compton wavelength for electron is
A. 
B. 
C. 
D. 
25.
The disagreement between Rayleigh-Jeans' predictions and experimental results for blackbody radiation spectrum is known as
A. 
B. 
C. 
D.