The work function of a metal is 1.6 × 10-19 J. When the metal surface is illuminated by the light of wavelength 6400 mathringA then the maximum kinetic energy of emitted photoelectrons will be (Planck's constant h=6.4 × 10-34 Js

Question

The work function of a metal is 1.6 × 10-19 J. When the metal surface is illuminated by the light of wavelength 6400 mathringA then the maximum kinetic energy of emitted photoelectrons will be (Planck's constant h=6.4 × 10-34 Js (A) 15 × 10-19 J (B) 2.8 × 10-19 J (C) 1.5 × 10-19 J (D) 4.5 × 10-19 J

Tardigrade Admin · Accepted Answer

W=1.6 × 10-19 J =1 eV (h c/λ)=W+K max λ=6400 mathringA=640 nm ; h c=1242 eV - nm ⇒ (1242 eV - nm /640 nm )=1 eV +K max ⇒ K max =(1.94 eV )-(1 eV ) =0.94 eV ×((1.6 × 10-19 J /1 eV ))=1.5 × 10-19 J .

Q. The work function of a metal is $1.6 \times 1 0^{- 19} J$ . When the metal surface is illuminated by the light of wavelength $6400 \overset{˚}{A}$ then the maximum kinetic energy of emitted photoelectrons will be (Planck's constant $h = 6.4 \times 1 0^{- 34} J s$

$15 \times 1 0^{- 19} J$

$2.8 \times 1 0^{- 19} J$

$1.5 \times 1 0^{- 19} J$

$4.5 \times 1 0^{- 19} J$

Q. The work function of a metal is 1.6×10−19J. When the metal surface is illuminated by the light of wavelength 6400A˚ then the maximum kinetic energy of emitted photoelectrons will be (Planck's constant h=6.4×10−34Js

15×10−19J

2.8×10−19J

1.5×10−19J

4.5×10−19J

W=1.6×10−19J=1eV λhc​=W+Kmax​ λ=6400A˚=640nm;hc=1242eV−nm ⇒640nm1242eV−nm​=1eV+Kmax​ ⇒Kmax​=(1.94eV)−(1eV) =0.94eV×(1eV1.6×10−19J​)=1.5×10−19J.

Q. The work function of a metal is $1.6 \times 1 0^{- 19} J$ . When the metal surface is illuminated by the light of wavelength $6400 \overset{˚}{A}$ then the maximum kinetic energy of emitted photoelectrons will be (Planck's constant $h = 6.4 \times 1 0^{- 34} J s$

$15 \times 1 0^{- 19} J$

$2.8 \times 1 0^{- 19} J$

$1.5 \times 1 0^{- 19} J$

$4.5 \times 1 0^{- 19} J$