SATHEE: Shortcut Methods

Shortcut Methods

JEE Mains

If the conductivity of a semiconductor is $1 S / m$ and the mobility of electrons is $μ_{n} = 0.14 m^{2} V^{- 1} s^{- 1}$ then the number of free electrons per unit volume will be $8 \times 10^{22} m^{- 3}$
In an intrinsic semiconductor, the mobility of electrons is $μ_{e} = 0.05 m^{2} V^{- 1} s^{- 1}$ and that of holes is $μ_{b} = 0.01 m^{2} V^{- 1} s^{- 1}$ . If equal number of donor and acceptor atoms with a concentration $5 \times 10^{21} m^{- 3}$ are added, what will be the conductivity of the new semiconductor?

Given, $μ_{e} = 0.05 m^{2} V^{- 1} s^{- 1}$ $μ_{h} = 0.01 m^{2} V^{- 1} s^{- 1}$ $n_{d} = n_{a} = 5 \times 10^{21} m^{- 3}$ $σ = n e μ_{n} + p e μ_{p}$ $= n_{d} e μ_{n} + n_{d} e μ_{p} ∵ n_{d} = n_{a}$ $= n_{d} (e μ_{n} + e μ_{p})$ $= n_{d} (0.05 + 0.01) \times 1.6 \times 10^{- 19}$ $n_{d} = 0.06 \times 1.6 \times 10^{- 19}$ $n_{d} = 9.6 \times 10^{- 21} m^{- 3}$

CBSE Board Exams

When a semiconductor is heated, its electrical conductivity increases whereas the conductivity of a metal decreases. Why?
What is the difference between intrinsic and extrinsic semiconductors?
The electrical conductivity of a semiconductor material can be increased by:

Adding impurities to the material.

Increasing the temperature of the material.

Both of the above.

What is the primary application of semiconductors in electronic devices?

Shortcut Methods

JEE Mains

CBSE Board Exams

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Mentorship

NCERT Exercise Video Solution

Shortcut Methods

JEE Mains

CBSE Board Exams

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Mentorship

NCERT Exercise Video Solution

Menu