Semiconductor Electronics: Materials, Devices and Simple Circuits MCQs for NEET — Physics Questions with Answers

There are no free electrons at room temperature

There are no free electrons at 0 K

The number of free electrons increases with rise of temperature

The charge carriers are electrons and holes

The donor level lies closely below the bottom of the conduction band

The donor level lies closely above the top of the valence band

The donor level lies at the halfway mark of the forbidden energy gap

None of above

When we heat a semiconductor its resistance increases

When we heat a semiconductor its resistance decreases

When we cool a semiconductor to 0 K then it becomes super conductor

Resistance of a semiconductor is independent of temperature

Positively charged

Negatively charged

Positively charged or negatively charged depending upon the type of impurity that has been added

Electrically neutral

 ${\mathrm{n}}_{\mathrm{e}}$ increases and ${\mathrm{v}}_{\mathrm{d}}$ decreases

 ${\mathrm{n}}_{\mathrm{e}}$ decreases and ${\mathrm{v}}_{\mathrm{d}}$ increases

Both ${\mathrm{n}}_{\mathrm{e}}$ and ${\mathrm{v}}_{\mathrm{d}}$ increases

Both ${\mathrm{n}}_{\mathrm{e}}$ and ${\mathrm{v}}_{\mathrm{d}}$ decreases

10888 Å                   

1088.8 Å

108.88 Å                   

10.888 Å

They carry negative charge

They are light

They mutually collide less

They require low energy to continue their motion

 ${\mathrm{\mu }}_{\mathrm{e}}$>${\mathrm{\mu }}_{\mathrm{h}}$               

 ${\mathrm{\mu }}_{\mathrm{e}}$<${\mathrm{\mu }}_{\mathrm{h}}$

 ${\mathrm{\mu }}_{\mathrm{e}}$= ${\mathrm{\mu }}_{\mathrm{h}}$             

 ${\mathrm{\mu }}_{\mathrm{e}}$<0; ${\mathrm{\mu }}_{\mathrm{h}}$>0

 $2.5\times {10}^{30} \mathrm{atoms}/{\mathrm{cm}}^3$                  

$1.0\times {10}^{13} \mathrm{atoms}/{\mathrm{cm}}^3$

$1.0\times {10}^{15} \mathrm{atoms}/{\mathrm{cm}}^3$                   

$2.5\times {10}^{36} \mathrm{atoms}/{\mathrm{cm}}^3$

Decreases exponentially with increasing band gap

Increases exponentially with increasing band gap

Decreases with increasing temperature

Is independent of the temperature and the band gap