CBSE Class 12 · 2020 · Modern PhysicsVery Short Answer

The variation of the stopping potential

V_{0}

with the frequency

ν

of the light incident on two different photosensitive surfaces

M_{1}

and

M_{2}

is shown in the figure. Identify the surface which has the greater value of work function.

Answer: Surface $M_{2}$ (larger threshold frequency).

Solution

The intercept of each line on the frequency axis is the threshold frequency

ν_{0}

, and the work function is

ϕ_{0} = h ν_{0}

.
The line for

M_{2}

meets the frequency axis at the larger

ν_{0}

, so

M_{2}

has the greater work function.

Surface M_{2}

CBSE Class 12 Board · 2020 · Subjective