All Problems

Thermal Radiation. Quantum Nature of Light.

Problem 5.279

A photoelectric current emerging in the circuit of a vacuum photocell when its zinc electrode is subjected to electromagnetic radiation of wavelength \(262 \mathrm{nm}\) is cancelled if an external decelerating voltage \(1.5 \mathrm{~V}\) is applied. Find the magnitude and polarity of the outer contact potential difference of the given photocell.

Reveal Answer
0.5 V; the polarity of the contact potential difference is opposite to that of external voltage.0.5 \mathrm{~V} ; \text { the polarity of the contact potential difference is opposite to that of external voltage.}