Physics

Problem

In a Frank-Hertz experiment, an electron of energy

5.6 \text{ eV}

passes through mercury vapour and emerges with an energy

0.7 \text{ eV}

. The minimum wavelength of photons emitted by mercury atoms is close to : [12 Jan. 2019 III] (a)

1700 \text{ nm}

(b)

2020 \text{ nm}

(c)

220 \text{ nm}

(d)

250 \text{ nm}