The light rays having photons of energy 1 ⋅ 8 eV are falling on a metal surface having a work function 1.2 eV. What is the stopping potential to be applied to stop the emitting electrons?

Question

The light rays having photons of energy 1 ⋅ 8 eV are falling on a metal surface having a work function 1.2 eV. What is the stopping potential to be applied to stop the emitting electrons? (A) 3 eV (B) 1.2 eV (C) 0.6 eV (D) 1.4 eV

Tardigrade Admin · Accepted Answer

Maximum kinetic energy of photoelectron ( KE ) max = E -φ =1.8-1.2 =0 ⋅ 6 eV i.e., e V0 =( KE ) max or e V0 =0.6 eV ∴ Stopping potential V0=0.6 eV.

Q. The light rays having photons of energy $1 \cdot 8 e V$ are falling on a metal surface having a work function $1.2 e V$ . What is the stopping potential to be applied to stop the emitting electrons?

3 eV

1.2 eV

0.6 eV

1.4 eV

Maximum kinetic energy of photoelectron
$(K E)_{m a x} = E - ϕ$
$= 1.8 - 1.2$
$= 0 \cdot 6 e V$
i.e., $e V_{0} = (K E)_{m a x}$
or $e V_{0} = 0.6 e V$
$∴$ Stopping potential $V_{0} = 0.6 e V$ .

Q. The light rays having photons of energy 1⋅8eV are falling on a metal surface having a work function 1.2eV. What is the stopping potential to be applied to stop the emitting electrons?