The wave function of a metal is 8.0 x \(10^{-19}\)J. Calculate the wavelength of its threshold frequency. (Speed of light in a vacuum = 3 x \(10^8ms^{-1}, Planck’s constant = 6.6 \times 10^{-34}\)Js)
- 0.8 x \(10^{-7}\)m
- 1 x \(10^{-7}\)m
-
2.3 x \(10^{-7}\)m
- 3.8 x \(10^{-7}\)m
- 12.4 x \(10^{-7}\)m
The correct answer is: C
Explanation
\(\theta = E - E_f = h_f = \frac{v}{\lambda} \Rightarrow = \lambda = \frac{h_v}{\theta}\frac{6.6\times 10^{-34} \times 3 \times 10^{8}}{8.6 \times 10^{-19}} = 0.8 \times 10^{-7}\)m