HSC Science (General) १२ वीं कक्षा - Maharashtra State Board Important Questions

The energy of photon of wavelength X is_____ .

[h = Planck’s constant, c = speed of light in vacuum]

The photoelectric work function for a metal surface is 2.3 eV. If the light of wavelength 6800A is incident on the surface of metal, find threshold frequency and incident frequency. Will there be an emission of photoelectrons or not?

[Velocity of light c = 3 x 10⁸ m/s,

Planck’s constant, h = 6.63 * 10^-34 Js ]

The threshold wavelength of silver is 3800Å. Calculate the maximum kinetic energy in eV of photoelectrons emitted, when ultraviolet light of wavelength 2600Å falls on it.

(Planck’s constant, h =6.63 x 1O^-34J.s.,

Velocity of light in air, c = 3 x 10⁸ m / s)

The photoelectric current in a photoelectric cell can be reduced to zero by a stopping potential of 1.8 volt. Monochromatic light of wavelength 2200Å is incident on the cathode. Find the maximum kinetic energy of the photoelectrons in joules. [Charge on electron = 1.6 x 10^-19 C]

The momentum of a photon of de Broglie wavelength 5000Å is _______.

[Planck’s constant = 6.63 x10^-34 J.s.]

Draw a neat labelled circuit diagram of experimental arrangement for study of photoelectric effect.

When radiations of wavelength λ₁ and λ₂ are incident on certain photosensitive, such that E₁ > E₂ . Then Planck's constant 'h' is ......................... .

(C = Velocity of light).

The photoelectric threshold wavelength of a metal is 230 nm. Determine the maximum kinetic energy in joule and in eV of the ejects electron for the metal surface when it is exposed to a radiation of wavelength 180 nm.

[Planck’s constant : h = 6.63 * 10^-34 Js, Velocity of light : C = 3 * 10⁸ m/s.]

Find the value of energy of electron in eV in the third Bohr orbit of hydrogen atom.

(Rydberg's constant (R) = 1· 097 x 10⁷m ^{- 1},Planck's constant (h) =6·63x10^-34 J-s,Velocity of light in air (c) = 3 x 10⁸m/ s.)

The photoelectric work function for a metal is 4.2 eV. If  the stopping potential is 3V, find the threshold wavelength and maximum kinetic energy of emitted electrons. 

(Velocity of light in air = 3 x 10⁸m/s,
Planck's constant = 6·63 x10^-34 J -s,
Charg.e ori electron = 1·6 x 10 ^-19 C)

Find the wave number of a photon having energy of 2.072 eV

Given : Charge on electron = 1.6 x 10^-19 C,

           Velocity of light in air = 3 x 10⁸ m/s,

           Planck’s constant = 6.63 x 10^-34 J-s.

The work functions for potassium and caesium are 2.25 eV and 2.14 eV respectively. Is the photoelectric effect possible for either of them if the incident wavelength is 5180 Å?

[Given : Planck’s constant = 6.63 x 10^–34 J.s.;
Velocity of light = 3 x 10⁸ m/s; 1 eV = 1.6 x 10^–19 J]

If the work function of a metal is 3 eV, calculate the threshold wavelength of that metal.
(Velocity of light = 3 x 10⁸ m/s, Planck’s constant = 6.63 x 10^–34 J.s.; 1 eV = 1.6 x 10^–19 J)

If the total energy of radiation of frequency 10¹⁴ Hz is 6.63 J, calculate the number of  photons in the radiation. (Planck’s constant = 6.63 x 10^–34 J.s.)

Draw a well labelled diagram of photoelectric cell.

Explain the observations made by Hertz and Lenard about the phenomenon of photoelectric
emission.

The number of photoelectrons emitted _______.

(A) varies inversely with frequency

(B) varies directly with frequency

(C) varies inversely with intensity

(D) varies directly with intensity

The momentum associated with the photon is given by_______.

(a) hv

(b) `"hv"/c`

(c) hE

(d) hλ

The work function for a metal surface is 2.2eV. If the light of wavelength 5000Å is incident on the surface of the metal, find the threshold frequency and incident frequency. Will there be an emission of photoelectrons or not? (c = 3 x 10⁸ m/ s, 1eV = 1.6x10^-19 J , h = 6.63 x 10^-34 J.s.)

What is photoelectri effect ? Defin (i) Stopping potential (ii) Photoelectric work function.