Question

Wavelength of photon having energy 2 $eV$:

• A. $6.20\times {10}^4\stackrel{o}{A}$
• B. $6.20\times {10}^3\stackrel{o}{A}$
• C. $6.20\times {10}^2\stackrel{o}{A}$
• D. $6.20\times {10}^5\stackrel{o}{A}$

Answer 1

The correct option is B $6.20\times {10}^3\stackrel{o}{A}$

We know that:
$1eV=1.6\times {10}^{-19}J$
$\lambda =\frac{hc}{E}=\frac{6.62\times {10}^{-34}\times 3\times {10}^8}{2\times 1.6\times {10}^{-19}}=6.20\times {10}^3\stackrel{o}{A}$