⇒Semiconductor

1. ⇒  (MHT CET 2023 11th May Morning Shift )

In energy band diagram of insulators, a band gap and the conduction band is respectively

A. very low and partially filled.

B. very high and completely filled.

C. very high and empty.

D. very low and empty.

2. ⇒  (MHT CET 2023 10th May Evening Shift )

A pure $\mathrm{Si}$ crystal has $4\times {10}^{28}$ atoms per ${\mathrm{m}}^3$. It is doped by 1 ppm concentration of antimony. The number of free electrons available will be

A. $4\times {10}^{34}{\mathrm{m}}^{-3}$

B. $4\times {10}^{28}{\mathrm{m}}^{-3}$

C. $4\times {10}^{22}{\mathrm{m}}^{-3}$

D. $4\times {10}^{20}{\mathrm{m}}^{-3}$

3. ⇒  (MHT CET 2023 10th May Morning Shift )

In insulators

A. valence band is empty and conduction band is filled with electrons.

B. conduction band is empty and valence band is completely filled with electrons.

C. valence band is partially filled.

D. conduction band is partially filled with electrons.

4. ⇒  (MHT CET 2023 9th May Morning Shift )

For an intrinsic semiconductor $({\mathrm{n}}_{\mathrm{h}}$ and ${\mathrm{n}}_{\mathrm{e}}$ are the number of holes per unit volume and number of electrons per unit volume respectively)

A. ${\mathrm{n}}_{\mathrm{h}}<{\mathrm{n}}_{\mathrm{e}}$

B. ${\mathrm{n}}_{\mathrm{h}}={\mathrm{n}}_{\mathrm{e}}$

C. ${\mathrm{n}}_{\mathrm{h}}=\frac{{\mathrm{n}}_{\mathrm{c}}}{2}$

D. ${\mathrm{n}}_{\mathrm{h}}>{\mathrm{n}}_{\mathrm{e}}$

5. ⇒  (MHT CET 2021 20th September Evening Shift )

In the case of insulators, a band gap and conduction band is respectively

A. very high empty.

B. very low, partially filled

C. very high, completely filled

D. very low, empty.