Q173 / 180 · COMEDK 2024 (Morning Shift) · Physics
Though $\mathrm{Sn}$ and $\mathrm{Si}$ are $4^{\text {th }}$ group elements, $\mathrm{Sn}$ is a metal while $\mathrm{Si}$ is a semiconductor because
- A$\mathrm{Sn}$ has more holes than $\mathrm{Si}$
- Correct answerBThe energy gap of $\mathrm{Sn}$ is zero volt while that of $\mathrm{Si}$ is $0.07 \mathrm{~V}$
- CThe energy gap of $\mathrm{Sn}$ is $1.1 \mathrm{~eV}$ volt while that of $\mathrm{Si}$ is $0.07 \mathrm{~V}$
- D$\mathrm{Sn}$ has more electrons than $\mathrm{Si}$
Solution
The electrical nature of a material depends on the energy gap between the valence band and the conduction band.
In Sn (white tin), the valence and conduction bands overlap, giving an effective energy gap of zero. Electrons can move freely, making it a metal.
In Si, there is a small but finite energy gap (~1.1 eV), allowing only limited electron excitation at room temperature, making it a semiconductor.
Among the given options, the defining characteristic is that the energy gap of Sn is zero while that of Si is finite (given as 0.07 V in the options). The correct option is (2).
In Sn (white tin), the valence and conduction bands overlap, giving an effective energy gap of zero. Electrons can move freely, making it a metal.
In Si, there is a small but finite energy gap (~1.1 eV), allowing only limited electron excitation at room temperature, making it a semiconductor.
Among the given options, the defining characteristic is that the energy gap of Sn is zero while that of Si is finite (given as 0.07 V in the options). The correct option is (2).
Hence, the correct answer is option: 'B'.