Question

The work function of tungsten is $4.50$ eV. The wavelength of fastest electron emitted when light whose photon energy is $5.50$ eV falls on tungsten surface, is?

• A. $12.27\stackrel{o}{A}$
• B. $0.286\stackrel{o}{A}$
• C. $12400\stackrel{o}{A}$
• D. $1.227\stackrel{o}{A}$

Answer 1

The correct option is A $12.27\stackrel{o}{A}$

$E=5.5eV$

$\varphi =4.5eV$

$K.E=E-\varphi =5.5-4.5=1eV$

$\lambda$= $\frac{6.6\times {10}^{34}}{\sqrt{2\times 9.1\times {10}^{-31}\times 1\times 1.16\times 10^{-19}}}$

$1.24\times {10}^{9}m=1.24\stackrel{o}{A}$