Question

If the frequency of light in a photoelectric experiment is doubled, the stopping potential will
(a) be doubled
(b) be halved
(c) become more than double
(d) become less than double

Answer 1

If the frequency of light in a photoelectric experiment is doubled ,the stopping potential will be

(c)become more than double

Reason:-

eV₀= hν-hν₀ ..................(i)

if frequency is doubled then

eV¹₀= 2hν-hν₀..................(ii)

multiplying equation (i) by 2 and then compare bothe equation

Now we will compare both the equation

2hν-hν₀ >2(hν-hν₀)

-ν₀ > -2ν₀

V¹₀>V₀

Answer 2

If the frequency of light in a photoelectric experiment is doubled, the stopping potential will become more than double.

Explanation:

As per the photoelectric effect equation of Einstein,  

$e V 0=h v-\varphi$

$\Rightarrow V 0=h v-\varphi e$   …1

where, v = frequency of light, V0 = stopping potential, φ= work function

Let the light’s conforming stopping potential be V0‘and new frequency be 2ν.

So,

$e V 0^{\prime}=2 h v-\varphi e$   …(2)

When both sides of equation (1) is multiplied by 2, we obtain:

$2 \mathrm{VO}=2 \mathrm{hv}-2 \varphi \mathrm{e}$  …(3)

When equation (2) is compared with (3), it can be seen that:

$2 h v-2 \varphi e<2 h v-\varphi e$

$\Rightarrow 2 V 0<V 0^{\prime}$

From these equations, it can be known that if there is a doubling of the light’s frequency in a photoelectric experiment, there will be more stopping potential.