A beam of cathode rays is subjected to crossed Electric(E) and Magnetic fields(B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by: (Where […]
A 5 watt source emits monochromatic light of wavelength 5000Å. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.. m, the […]
A source of light is placed at a distance of 50 cm from a photocell and the stopping potential is found to be V₀. If the distance between the light source and photocell is made […]
A 200 W sodium street lamp emits yellow light of wavelength 0.6 µm. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per […]
What is the energy of photon whose wavelength is 6840 Å?
Options
(a) (1.81 eV) (b) (3.6 eV) (c) (-13.6 eV) (d) (12.1 eV)
Correct Answer:
(1.81 eV)
Explanation:
λ = 6840 Å .·. […]
The ionization energy of Li⁺⁺ is equal to
Options
(a) 9hcR (b) 6hcR (c) 2hcR (d) hcR
Correct Answer:
9hcR
Explanation:
Ionisation energy of Li⁺⁺ = 9hcR
Ionisation energy = RchZ² = Rhc(3)² = […]
The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV, and the stopping potential for a radiation incident on this surface 5 V. The incident radiation lies in
Options
If alpha, beta and gamma rays carry same momentum, which has the longest wavelength
Options
(a) Alpha rays (b) Beta rays (c) Gamma rays (d) None, all have same wavelength
Correct Answer:
None, […]
Photoelectric current from a given photocell will depend upon
Options
(a) Number of photons striking per second (b) Frequency of incident photon (c) Material of the target (d) None of the above
Correct […]
If by mistake voltmeter is connected in series and ammeter in parallel then
Options
(a) both are damaged (b) ammeter is damaged (c) voltmeter is damaged (d) none of these
Correct Answer:
none of […]
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