The work function of a metal is 2.5 eV. The maximum kinetic energy of the photoelectrons emitted if a radiation of wavelength 3000 $A^{o}$ falls on it is :
( $h = 6.63 \times 1 0^{- 34}$ Js and $c = 3 \times 1 0^{8}$ m/s)

Question

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Answer 1

Maximum kinetic energy, $K . E ._{m a x} = \frac{h c}{λ} - ϕ$

$= \frac{6 . 6 3 \times 1 0 ^{- 34} \times 3 \times 1 0 ^{8}}{3 0 0 0 \times 1 0 ^{- 10}} - 2.5 \times 1.6 \times 1 0^{- 19}$

$= (6.63 \times 1 0^{- 19} - 4 \times 1 0^{- 19}) J$

$= 2.63 \times 1 0^{- 19} J$ .
So, the answer is option (D).

Answer 2

Maximum kinetic energy,

K . E ._{m a x} = \frac{h c}{λ} - ϕ

= \frac{6 . 6 3 \times 1 0 ^{- 34} \times 3 \times 1 0 ^{8}}{3 0 0 0 \times 1 0 ^{- 10}} - 2.5 \times 1.6 \times 1 0^{- 19}

= (6.63 \times 1 0^{- 19} - 4 \times 1 0^{- 19}) J

= 2.63 \times 1 0^{- 19} J

.

So, the answer is option (D).

The work function of a metal is 2.5 eV. The maximum kinetic energy of the photoelectrons emitted if a radiation of wavelength 3000 $A^{o}$ falls on it is :
( $h = 6.63 \times 1 0^{- 34}$ Js and $c = 3 \times 1 0^{8}$ m/s)

$1.12 \times 1 0^{- 19} J$

$4.8 \times 1 0^{- 19} J$

$3.2 \times 1 0^{- 19} J$

$2.63 \times 1 0^{- 19} J$

A radiation of wave length 2500 $A^{0}$ is incident on a metal plate whose work function is 3.5 eV. Then the potential required to stop the fastest photo electrons emitted by the surface is :
( $h = 6.63 \times 1 0^{- 34}$ Js and $c = 3 \times 1 0^{8}$ m/s)

Photons of energy 5 eV are incident on the cathode. Electrons reaching the anode have kinetic energies varying from 6 eV to 8 eV. Find the work function of the metal and state whether the current in the circuit is less than or equal to saturation current in eV.

If the intensity of radiation incident on a photocell be increased four times, then the number of photoelectrons and the energy of photoelectrons emitted respectively become

A photometal is illuminated by lights of wavelengths $λ_{1} a n d λ_{2}$ respectively. The maximum kinetic enegies of electrons emitted in the two cases are $E_{1}$ and $E_{2}$ respectively. The work function of metal is

The stopping potential for the photoelectrons emitted from a metal surface of work function 1.7 eV is 10.4 V. Find the wavelength of the radiation in $A 0$

Revise with Concepts

Introduction to Dual Nature

Electron Emission

Observations on Photo Electric Effect

Experimental Study of Photoelectric Effect

Photo Electric Effect of Light and Wave Theory of Light

Planck's Photon Hypothesis

Photon Energies

The work function of a metal is 2.5 eV. The maximum kinetic energy of the photoelectrons emitted if a radiation of wavelength 3000Ao falls on it is :(h=6.63×10−34 Js and c=3×108 m/s)

1.12×10−19J

4.8×10−19J

3.2×10−19J

2.63×10−19J

Maximum kinetic energy, K.E.max​=λhc​−ϕ =3000×10−106.63×10−34×3×108​−2.5×1.6×10−19 =(6.63×10−19−4×10−19)J =2.63×10−19J.So, the answer is option (D).

A radiation of wave length 2500 A0 is incident on a metal plate whose work function is 3.5 eV. Then the potential required to stop the fastest photo electrons emitted by the surface is : (h=6.63×10−34Js and c=3×108 m/s)

Photons of energy 5 eV are incident on the cathode. Electrons reaching the anode have kinetic energies varying from 6 eV to 8 eV. Find the work function of the metal and state whether the current in the circuit is less than or equal to saturation current in eV.

If the intensity of radiation incident on a photocell be increased four times, then the number of photoelectrons and the energy of photoelectrons emitted respectively become

A photometal is illuminated by lights of wavelengths λ1​ and λ2​ respectively. The maximum kinetic enegies of electrons emitted in the two cases are E1​ and E2​ respectively. The work function of metal is

The stopping potential for the photoelectrons emitted from a metal surface of work function 1.7 eV is 10.4 V. Find the wavelength of the radiation in A0

Revise with Concepts

Introduction to Dual Nature

Electron Emission

Observations on Photo Electric Effect

Experimental Study of Photoelectric Effect

Photo Electric Effect of Light and Wave Theory of Light

Planck's Photon Hypothesis

Photon Energies

The work function of a metal is 2.5 eV. The maximum kinetic energy of the photoelectrons emitted if a radiation of wavelength 3000 $A^{o}$ falls on it is :
( $h = 6.63 \times 1 0^{- 34}$ Js and $c = 3 \times 1 0^{8}$ m/s)

$1.12 \times 1 0^{- 19} J$

$4.8 \times 1 0^{- 19} J$

$3.2 \times 1 0^{- 19} J$

$2.63 \times 1 0^{- 19} J$

A radiation of wave length 2500 $A^{0}$ is incident on a metal plate whose work function is 3.5 eV. Then the potential required to stop the fastest photo electrons emitted by the surface is :
( $h = 6.63 \times 1 0^{- 34}$ Js and $c = 3 \times 1 0^{8}$ m/s)

A photometal is illuminated by lights of wavelengths $λ_{1} a n d λ_{2}$ respectively. The maximum kinetic enegies of electrons emitted in the two cases are $E_{1}$ and $E_{2}$ respectively. The work function of metal is

The stopping potential for the photoelectrons emitted from a metal surface of work function 1.7 eV is 10.4 V. Find the wavelength of the radiation in $A 0$