Question

2. A photon of wavelength for 4 x10 -7 m strikes on the metal surface the work

Answer 1

Answer:

See explanation

Explanation:

Energy of the photon;

E = hc/λ

h= Planks constant

c= speed of light

λ = wavelength

E= 6.6 × 10^-34 × 3 × 10^8/4 x10 -7

E = 4.95 × 10^-19 J

If 1ev=1.602x10-19 J

x = 4.95 × 10^-19 J

x= 3.1 ev

From Einstein's photoelectric equation;

KE = E - Wo

Where;

KE = kinetic energy of ejected photoelectron

E= energy of the photon

Wo= work function of the metal

KE = 3.1 eV - 2.13 eV

KE= 0.97 eV

KE = 0.97 eV × 1.602x10-19 J

KE = 1.55 × 10^-19 J

KE = 1/2 mv^2

1.55 × 10^-19= 1/2 × 9.1 × 10^-31 × v^2

v= √2 × 1.55 × 10^-19/9.1 × 10^-31

v= 5.8 × 10^5 m/s