EASY
Earn 100

For photoelectric effect which of the following statements are true.
I) The kinetic energies of the photoelectrons do not depend on the frequency of light
II) Photoelectric effect will always occur for highly intense light
III) The maximum kinetic energy of photoelectron does not depend upon the intensity of the light
IV) The escaping electron's kinetic energy is larger for larger frequency

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Important Questions on Dual Nature of Matter and Radiation

MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
Light of wavelength 500 nm is incident on a metal with work function 2.28 eV. The de Broglie wavelength of the emitted electron is:
HARD
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
In a historical experiment to determine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectron energies were measured by applying a stopping potential. The relevant data for the wavelength (λ) of incident light and the corresponding stopping potential V0 are given below:
 
λμm V0volt
0.3 2.0
0.4 1.0
0.5 0.4

Given that c=3×108 m s-1 and e=1.6×10-19C,  Planck's constant (in units of J s) found from such an experiment is :
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
A laser light of wavelength 660 nm is used to weld Retina detachment. If a laser pulse of width 60 ms and power 0.5 kW is used, the approximate number of photons in the pulse are (Take Planck's Constant, h=6.62×10−34 J s)
HARD
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
The magnetic field associated with a light wave is given, at the origin, by B=B0 sin⁡3.14×107ct+sin⁡6.28×107ct. If this light falls on a silver plate having a work function of 4.7eV, what will be the maximum kinetic energy of the photoelectrons?
(c=3×108 m s−1,h=6.6×10−34 J s)
HARD
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
A metal plate of area 1×10-4 m2 is illuminated by a radiation of intensity 16 mW m-2 . The work function of the metal is 5 eV. The energy of the incident photons is 10 eV and only 10% of it produces photo electrons. The number of emitted photo electron  per second and their maximum energy, respectively, will be: 1 eV=1.6×10-19 J
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
Photons of energy 7 eV are incident on two metals A and B with work functions 6 eV and 3 eV, respectively. The minimum de-Broglie wavelengths of the emitted photoelectrons with maximum energies are λA and λB, respectively, where λAλB is nearly,
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
The maximum velocity of the photoelectrons emitted from the surface is v when light of frequency n falls on a metal surface. If the incident frequency is increased to 3n, the maximum velocity of the ejected photoelectrons will be:
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
When photons of wavelength λ1 are incident on an isolated sphere, the corresponding stopping potential is found to be V. When photons of wavelength λ2 are used, the corresponding stopping potential was thrice that of the above value. If light of wavelength λ3 is used then find the stopping potential for this case:
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
Photons with energy of 5 eV are incident on a cathode, C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C , no photoelectrons will reach the anode,  A , if, the stopping potential of A relative to C is
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular are of radius R by a perpendicular magnetic field having a magnitude B. The work function of the metal is (Where symbols have their usual meanings).
EASY
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
The photoelectric threshold wavelength of silver is 3250×10–10 m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength 2536×10–10 m is:-

Given h=4.14×10-15 eV s  and c=3×108 m s-1
EASY
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
Maximum kinetic energy of a photoelectric varies with the frequency f of the incident radiation as
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
When ultraviolet radiation of a certain frequency falls on a potassium target, the photoelectrons released can be stopped completely by a retarding potential of 0.6 V. If the frequency of the radiation is increased by 10%, this stopping potential rises to 0.9 V. The work function of potassium is
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect

In a photocell circuit, the stopping potential, V0 is a measure of the maximum kinetic energy of the photoelectrons. The following graph shows experimentally measured values of stopping potential versus frequency, ν of incident light.

Question Image

The values of Planck's constant and the work function as determined from the graph are (taking the magnitude of electronic charge to be, e=1.6×10-19 C),

MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
Radiation of wavelength λ is incident on a photocell. The fastest emitted photoelectron has a speed v. If the wavelength is changed to 3λ4, the speed of the fastest emitted photoelectron will be
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
A photoelectric material having work-function ϕ0 is illuminated with a light of wavelength λ λ<hcϕ0. The fastest photoelectron has a de Broglie wavelength λd. A change in wavelength of the incident light by Δλ results in a change Δλd in λd. The ratio ΔλdΔλ is proportional to
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
A photoelectric surface is illuminated successively by monochromatic light of wavelengths λ and λ2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface is :
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
On a photosensitive material, when the frequency of incident radiation is increased by 30%, the kinetic energy of emitted photoelectrons increases from 0.4 eV to 0.9 eV. The work function of the surface is
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
When a certain metallic surface is illuminated with monochromatic light of wavelength λ, the stopping potential for photoelectric current is 3V0 and when the same surface is illuminated with light of wavelength 2λ, the stopping potential is V0. The threshold wavelength of this surface for photoelectric effect is
MEDIUM
Physics>Modern Physics>Dual Nature of Matter and Radiation>Photoelectric Effect
When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is V4. The threshold wavelength for the metallic surface is: