Two different metals, X and Y

PHYSICS · Single correct · A Level · Physics · Particles and radiation · Particles and radiation

Problem

Two different metals, X and Y, are illuminated with the same range of light frequencies. Their

K_{\text{max}}

versus

f

graphs are straight, parallel lines. At a frequency of

8.0\times10^{14}\,\text{Hz}

the measured kinetic energies are

1.5\,\text{eV}

for metal X and

0.5\,\text{eV}

for metal Y. Which statement about the relative work functions

\phi_X

and

\phi_Y

is most consistent with these data? (a)

\phi_X

is larger than

\phi_Y

by approximately

1.0\,\text{eV}

. (b)

\phi_X

is smaller than

\phi_Y

by approximately

0.5\,\text{eV}

. (c)

\phi_X

is smaller than

\phi_Y

by approximately

1.0\,\text{eV}

. (d)

\phi_X

is approximately equal to

\phi_Y