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
Verified Correct Answer: C.
Physical Principles & Numerical Solution
\(\theta = E - E_f = h_f = \frac{v}{\lambda} \Rightarrow = \lambda = \frac{h_v}{\theta}
\frac{6.6\times 10^{-34} \times 3 \times 10^{8}}{8.6 \times 10^{-19}} = 0.8 \times 10^{-7}\)m
Source: Myschool Past Questions Archive (Record #26274)