Photons with energy 5 eV are incident on cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach anode A; if the stopping potential (in volt) of A relative to C is (only magnitude)

Question

Photons with energy 5 eV are incident on cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach anode A; if the stopping potential (in volt) of A relative to C is (only magnitude) (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

e Vs=(1/2) m v max 2=h v-φ0 2-5-φ0 ⇒ φ0=3 eV In second case, e Vs=6-3=3 eV ⇒ Vs=3 V ∴ VA C=-3 V

Q. Photons with energy 5eV are incident on cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2eV. When photons of energy 6eV are incident on C, no photoelectrons will reach anode A; if the stopping potential (in volt) of A relative to C is (only magnitude)

eVs​=21​mvmax2​=hv−ϕ0​ 2−5−ϕ0​ ⇒ϕ0​=3eV In second case, eVs​=6−3=3eV ⇒Vs​=3V ∴VAC​=−3V

$e V_{s} = \frac{1}{2} m v_{m a x}^{2} = h v - ϕ_{0}$
$2 - 5 - ϕ_{0}$
$\Rightarrow ϕ_{0} = 3 e V$
In second case,
$e V_{s} = 6 - 3 = 3 e V$
$\Rightarrow V_{s} = 3 V$
$∴ V_{A C} = - 3 V$