Question

A ray of yellow light has a wavelength of about 5.8×10−7 m. Will exposure to yellow light cause electrons to be emitted from cesium?

Answer 1

The threshold frequency of Cesium is 5.2 x 10^14 Hz.

To find the frequency of yellow light, we use the equation:
speed of light = wavelength x frequency
3 x 10^8 = 5.8 x 10^-17 x frequency
frequency = 5.17 x 10^24

This is higher than the threshold frequency of Cesium, thus, electrons will be emitted.