If h is Planck's constant, the momentum of a photon of wavelength 0.01 Å is
h × 10-2
h
h × 102
h × 1012
Which of the following are thermions?
protons
electrons
photons
positrons
Which one of the following statements is wrong in the context of X-rays generated from an X-ray tube?
Wavelength of characteristic X-rays decreases when the atomic number of the target increases.
Cut-off wavelength of the continuous X-rays depends on the atomic number of the target.
Intensity of the characteristic X-rays depends on the electrical power given to the X-ray tube.
Cut-off wavelength of the continuous X-rays depends on the energy of the X-ray tube.
The de - Broglie wave corresponding to a particle of mass m and velocity v has a wavelength associated with it is
h/mν
hmν
mh/ν
m/hν
When the atoms in a sample of hydrogen like atoms are in the fourth (n = 4) orbit, how many spectral lines will be emitted in the radiation spectrum of the sample?
4
5
6
9
If the wavelength of Hα line of the Balmer series of the hydrogen spectum is λ the wavelength of the
Hβ line is 7/20 λ
Least energetic spectral line of the Lyman series is 5/27 λ
Ionisation potential of hydrogen is hc/λ
All the above are true
Bragg's equation will have no solution, if
λ > 2d
λ < 2d
λ < d
λ = d
A photon of energy 10.2 eV corresponds to light of wavelength λ0. Due to an electron transition from n = 2 to n = 1 in a hydrogen atom, light of wavelength λ is emitted. If we take into account the recoil of an atom, when a photon is emitted,
λ = λ0
λ < λ0
λ > λ0
The data is not sufficient to reach a conclusion.
Gases begin to conduct electricity at low pressure because
at low pressures gases turn to plasma
colliding electrons can acquire higher kinetic energy due to increased mean free path leading to ionisation of atoms
atoms break up into electrons and protons
the electrons in atoms can move freely at low pressures
Photon of frequency v has a momentum associated with it. If c is the velocity of light, the momentum is
v/c
hvc
hv/c2
hv/c
