An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is
Options
(a) (E/2m)¹∕₂ (b) c(2mE)¹∕₂ (c) 1/c (2m/E)¹∕₂ (d) 1/c (E/2m)¹∕₂
Correct Answer: […]
The energy of groundstate (n=1) of hydrogen level is -13.6 eV. The ionistation potential of the hydrogen atom is
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(a) (-13.6 eV) (b) (13.6 V) (c) (+13.6 eV) (d) more than (-13.6 […]
A and B are two metals with threshold frequencies 1.8 x 10¹⁴ Hz and 2.2 x 10¹⁴ Hz. Two identical photons of energy 0.825 eV each are incident on them. Then photoelectrons are emitted in […]
An electron is
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(a) Hardon (b) Baryon (c) a nucleon (d) a lepton
Correct Answer:
a lepton
Explanation:
No explanation available. Be the first to write the explanation for this question by […]
Hard X-rays for the study of fractures in bones should have a minimum wavelength of 10⁻¹¹ m. The accelerating voltage for electrons in X-ray machine should be
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(a) <124.2 kV (b) >12.4 KV […]
According to photon theory of light which of the following physical quantities, associated with a photon, do not/does not change as it collides with an electron in vacuum
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(a) Speed and momentum […]
CO₂ laser uses
Options
(a) Microwaves (b) Infra red (c) Ultra violet (d) Visible light
Correct Answer:
Ultra violet
Explanation:
No explanation available. Be the first to write the explanation for this question […]
A photosensitive metallic surface has work function, hν₀. If photons of energy 2hν₀ fall on this surface, the electrons come out with a maximum velocity of 4×10⁶m/s. When the photon energy is increased to 5hν₀, […]
During production of cathode ray
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(a) d.c. source is connected across cathode ray tube (b) a.c. source is connected across cathode ray tube (c) Electric field is perpendicular to magnetic field (d) […]
Excitation energy of a hydrogen like ion, in its first excitation state, is 40.8 eV. The energy needed to remove the electron from the ion in ground state is
Options
(a) 13.6 eV […]
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