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JEE Mains · Physics · STD 12 - 11. Dual nature of radiation and matter
In a photoelectric experiment ultraviolet light of wavelength \(280\, {nm}\) is used with lithium cathode having work function \(\phi=2.5\, {eV}\). If the wavelength of incident light is switched to \(400\, {nm}\), find out the change in the stopping potential (in \({V}\)). \(\left({h}=6.63 \times 10^{-34}\, {J} \cdots\right.\), \(\left.{c}=3 \times 10^{8} \,{ms}^{-1}\right)\)
- A \(1.3\)
- B \(1.1\)
- C \(1.9\)
- D \(0.6\)
Answer & Solution
Correct Answer
(A) \(1.3\)
Step-by-step Solution
Detailed explanation
\({KE}_{\max }={eV}_{{S}}=\frac{{h} {c}}{\lambda}-\phi\) \(\Rightarrow {eV}_{{S}}=\frac{1240}{280}-2.5=1.93\, {eV}\) \(\rightarrow {V}_{{S}_{1}}=1.93\, {V} \ldots\) (i) \(\rightarrow {eV}_{{S}_{2}}=\frac{1240}{400}-2.5=0.6 \,{eV}\) \(\Rightarrow {V}_{{S}_{2}}=0.6 \,{V} \ldots\)…
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