JEE Main · 2019 · 09 Jan 2019 · Shift 1 · Current Electricity

Mobility of electron in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an

n

-type semiconductor, the density of electrons is

1 0^{19} m^{- 3}

and their mobility is

1.6 m^{2} / (V . s)

then the resistivity of the semiconductor (since it is an n type semiconductor contribution of holes is ignored) is close to:

Answer: (C)

Solution

Conductivity of the n-type material is

σ = n e μ = 1 0^{19} \times 1.6 \times 1 0^{- 19} \times 1.6 = 2.56

S/m, counting only the electrons as instructed. Resistivity is its reciprocal,

ρ = \frac{1}{σ} = \frac{1}{2.56} \approx 0.4 Ω m

JEE Main · 2019 · 09 Jan 2019 · Shift 1 · Single correct option