JEE Main · 2026 · 04 Apr 2026 · Shift 1 · Modern Physics

The graph shows variation of stopping potential

V_{o}

with the frequency

ν

of the incident radiation for three photosensitive metals

X_{1}

X_{2}

and

X_{3}

. Which metal will give out electrons with greater kinetic energy, for the same wavelength of incident radiation?

Answer: (A)

Solution

For each metal Einstein's equation gives

e V_{0} = h ν - ϕ

, so the stopping-potential line meets the frequency axis at the threshold frequency

ν_{0} = ϕ / h

. The graph shows

X_{1}

crossing the axis at the lowest frequency,

1.0 \times 1 0^{14}

Hz, so

X_{1}

has the smallest work function. For a common incident wavelength the kinetic energy

h ν - ϕ

is greatest where

ϕ

is smallest, so the electrons of highest kinetic energy come from

X_{1}

JEE Main · 2026 · 04 Apr 2026 · Shift 1 · Single correct option