The longest wavelength that can be absorbed by silicon, which has the band gap of 1.12 eV, is 1.1 μm. If the longest wavelength that can be absorbed by another material is 0.87 μm, then the band gap of this material is approximately

Wavelength: Wavelength is the distance between two successive peaks in a wave. It represents the distance between two consecutive points in the wave where the electromagnetic field has the same phase.

\(\lambda_c = \frac{k}{E_g}\)

Where, 

\(\lambda_c \) = Wavelength.

\( E_g\) = Energy band gap.

k = constant.

Let, \(\lambda_{c1} = \frac{k}{E_{g1}}\)

1.1 \(\mu m\) = \(\frac{k}{1.12 eV} \Rightarrow k = 1.1\times 1.12\)

\(\lambda_{c2} = \frac{k}{E_{g2}}\)

\(E_{g2} = \frac{(1.1)(1.12)}{0.87} = 1.416 eV.\)

Here, option 1 is correct.