If the frequency of the incident light is doubled, the kinetic energy of the emmitted electron will be

Question

If the frequency of the incident light is doubled, the kinetic energy of the emmitted electron will be (A) zero (B) reduced to (1/3) (C) also doubled (D) None of these

Tardigrade Admin · Accepted Answer

From Planck's law, energy of emitted electrons is

E = h v

where

h

is Planck's constant,

v

the frequency.

∴

Given,

v_{2} = 2 v_{1}

∴ \frac{E _{2}}{E _{1}} = \frac{v _{2}}{v _{1}}

\Rightarrow E_{2} = \frac{2 v _{1}}{r _{1}} E_{1}

= 2 E_{1}

Hence, energy of emitted electrons is also doubled.

Q. If the frequency of the incident light is doubled, the kinetic energy of the emmitted electron will be

zero

reduced to $\frac{1}{3}$

also doubled

None of these

Q. If the frequency of the incident light is doubled, the kinetic energy of the emmitted electron will be

zero

reduced to 31​

also doubled

None of these

From Planck's law, energy of emitted electrons is E=hv where h is Planck's constant, v the frequency. ∴ Given, v2​=2v1​ ∴E1​E2​​=v1​v2​​ ⇒E2​=r1​2v1​​E1​ =2E1​ Hence, energy of emitted electrons is also doubled.

reduced to $\frac{1}{3}$