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The wave function of a metal is 8.0 x \(10^{-19}\)J. Calcula...

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)

A.

0.8 x \(10^{-7}\)m

B.

1 x \(10^{-7}\)m

C.

2.3 x \(10^{-7}\)m

D.

3.8 x \(10^{-7}\)m

E.

12.4 x \(10^{-7}\)m

Correct answer is C

\(\theta = E - E_f = h_f = \frac{v}{\lambda} \Rightarrow = \lambda = \frac{h_v}{\theta}
\frac{6.6\times 10^{-34} \times 3 \times 10^{8}}{8.6 \times 10^{-19}} = 0.8 \times 10^{-7}\)m