CAPE Physics Unit 2 · 2015 · Paper 1 · Question Q31

A monochromatic light source emits 0.5\text{ watts} of power. The light has a frequency of 5.0 \times 10^{15}\text{ Hz} and 1\% of the photons fall on a photocell. The number of photons incident on the photocell per second is

1. (A)3.31 \times 10^{-18}
2. (B)6.63 \times 10^{16}
3. (C)1.51 \times 10^{15}
4. (D)1.51 \times 10^{17}