Dual Nature of Matter

JEE Main level, single correct, medium

158 of 200

Question 158 of 200

Two identical photocathodes receive the light of frequencies f1{f}_{1} and f2{f}_{2} respectively. If the velocities of the photo-electrons coming out are v1{v}_{1} and v2{v}_{2} respectively, then

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Answer: (A) v12−v22=2hm[f1−f2]{v}_{1}^{2}-{v}_{2}^{2}=\dfrac{2h}{m}[{f}_{1}-{f}_{2}]

12mv12=hf1−ϕ\dfrac{1}{2}m{v}_{1}^{2}=h{f}_{1}-\phi
12mv22=hf2−ϕ\dfrac{1}{2}m{v}_{2}^{2}=h{f}_{2}-\phi
v12−v22=2hm(f1−f2){v}_{1}^{2}-{v}_{2}^{2}=\dfrac{2h}{m}\left({f}_{1}-{f}_{2}\right)

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