Question

When the energy of the incident radiation is incredased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is ?​

Answer 1

Answer:

ø = 1 eV

Explanation:

Let energy of incident radiation be E

» E1 = E

» E2 = E + (20/100)E

E2 = E +E/5

E2 = 6E/5

(K.E)1 = 0.5 eV

(K.E)2 = 0.8 eV

From Photoelectric equation:

hv = ø + K.E

ø = hv - K.E

ø = E - 0.5 -------(1)

ø = 6E/5 - 0.8 ------(2)

Equating (1) & (2)

E - 0.5 = 6E/5 - 0.8

E/5 = 0.3

E = 1.5 eV

ø = 1.5 - 0.5 = 1.0 eV