CURRENT ELECTRICITY
Q-Define the term thermal velocity of electron. What is its average value?
A- When potential not applied at then ends of conductor , velocity of electron in the conducting body is known as thermal velocity. It is in the order of 10^5 m/s.
Q-What is drift velocity. what is its average value.
A- When external potential is applied, source cell is connected, electron inside the conductor starts moving with a particular velocity in a fixed direction. this time velocity of electron is known as drift velocity. average value of drift velocity is in the order of 10^-5 cm /sec.
Q-Define the term ‘electrical conductivity’ of a metallic wire. Write its S.I. unit.
A-Conductivity. The reciprocal of the resistivity of the material of a conductor is called its conductivity.
its unit is ohm^-1.m^-1
Q-Derive an expression for drift velocity of free electrons in a conductor in terms of relaxation time.
A-Watch video solution. Click below.
Q-Ohmic circuit always follows ohms law. those who not follows ohms law , follows?
A- childs law
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Q-Define the term current density. How it is related to drift velocity.
A- Magnitude of electric current passes through unit cross sectional area is known as current density.
current density is denoted by j.
j=neA.vd
n= number of electron in per unit volume, A=cross-sectional area , v d = drift velocity