This question has Statement -1 and Statement -2 . Of the four choices given after the statements, choose the one that best describes the two statements. Statement-1 : A metallic surface is irradiated by a monochromatic light of frequency $\mathrm{v}>\mathrm{v}_{0}$ (the threshold frequency). The maximum kinetic energy and the stopping potential are $\mathrm{K}_{\max }$ and $\mathrm{V}_{0}$ respectively. If the frequency incident on the surface doubled, both the $\mathrm{K}_{\max }$ and $\mathrm{V}_{0}$ are also doubled. Statement-2 : The maximum kinetic energy and the stopping potential of photoelectrons emitted from a surface are linearly dependent on the frequency of incident light.

(C) Statement-1 is false, Statement-2 is true.

(A) Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation of Statement-1.

(B) Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.

(D) Statement-1 is true, Statement-2 is false.

JEE Main · 2011 · 10 Apr 2011 · Offline · Modern Physics

This question has Statement -1 and Statement -2 . Of the four choices given after the statements, choose the one that best describes the two statements.
Statement-1 : A metallic surface is irradiated by a monochromatic light of frequency

v > v_{0}

(the threshold frequency). The maximum kinetic energy and the stopping potential are

K_{m a x}

and

V_{0}

respectively. If the frequency incident on the surface doubled, both the

K_{m a x}

and

V_{0}

are also doubled.
Statement-2 : The maximum kinetic energy and the stopping potential of photoelectrons emitted from a surface are linearly dependent on the frequency of incident light.

(A)Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation of Statement-1.
(B)Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.
(C)Statement-1 is false, Statement-2 is true.✓ Correct
(D)Statement-1 is true, Statement-2 is false.

Answer: (C)

Solution

The photoelectric relations

K_{m a x} = h ν - h ν_{0}

and

e V_{0} = h ν - h ν_{0}

are both straight-line relations in the frequency

ν

, so the second statement is true. But linear is not the same as proportional: when

ν

is doubled,

K_{m a x}

becomes

2 h ν - h ν_{0}

, which is more than twice the original

h ν - h ν_{0}

unless the threshold

ν_{0}

were zero. So

K_{m a x}

and

V_{0}

do not simply double, and the first statement is false while the second is true.

JEE Main · 2011 · 10 Apr 2011 · Offline · Single correct option

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JEE Main · 2011 · 10 Apr 2011 · Offline · Modern Physics

Solution

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