Correct Answer - A
Here, `E_g` =0.72 eV = `0.72 xx 1.6 xx 10^(-19) J`
If `lambda` is the maximum wavelength of electromagnetic radiation which can create a hole- electron pair in germanium, then `E_g=(hc)/lambda`
or `lambda=(hc)/E_g=(6.62xx10^(-34)xx3xx10^8)/(0.72xx1.6xx10^(-19))=1.7 xx 10^(-6) m`