Question

The chart shows the frequencies of certain colors of visible light.

A 2 column table with 4 rows. The first column is labeled light with entries red, violet, green, orange. The second column is labeled frequency in hertz with entries 4.5 times 10 Superscript 14 baseline, 7.5 times 10 Superscript 14 baseline, 6.0 times 10 Superscript 14 baseline, 5.0 times 10 Superscript 14 baseline.
Which colors will eject electrons when they strike sodium, which has a frequency threshold of 5.7 × 1014 Hz?

violet and green
red and orange
violet only
red, violet, green, and orange

Answer 1

Violet and green.

Both have frequencies above the threshold (7.5×10^14 Hz and 6.0×10^14 Hz > 5.7×10^14 Hz), so they can eject electrons; red and orange are below threshold.