Question 229: Dual Nature of Matter and Radiation

Question

The stopping potential for photoelectrons emitted from a surface illuminated by light of wavelength 6630 $$\mathop A\limits^o $$ is 0.42 V. If the threshold frequency is x $$	imes$$ 10
13
/s, where x is _________ (nearest integer).
(Given, speed light = 3 $$	imes$$ 10
8
m/s, Planck's constant = 6.63 $$	imes$$ 10
$$-$$34
Js)

Accepted Answer

$${{hc} \over \lambda } - \phi  = KE = e{V_0}$$
$$ \Rightarrow {{6.63 	imes {{10}^{ - 34}} 	imes 3 	imes {{10}^8}} \over {6630 	imes {{10}^{ - 10}}}} - 6.63 	imes {10^{ - 34}}{f_{th}} = 1.6 	imes {10^{ - 19}} 	imes 0.4$$
$$ \Rightarrow {f_{th}} \simeq 35.11 	imes {10^{13}}\,H$$

Dual Nature of Matter and Radiation

Integer / Numeric Answer Type