|
Drift velocity is the average uniform velocity acquired by free electrons inside a metal by the application of an electric field which is responsible for current through it. Drift speed is very low it is of the order of 10-4 m/s as compared to thermal speed of electrons at room temperature.
If suppose for a conductor
n = Number of electron per unit volume of the conductor
A = Area of cross-section
V = Potential difference across the conductor
E = Electric field inside the conductor
|
|
i = Current, J = Current density, ρ = Specific resistance, σ = conductivity then current relates with drift velocity as i = neAvd we can also write
1. The direction of drift velocity for electron in a metal is opposite to that of applied electric field (i.e. current density ).
vd ∝ E i.e., greater the electric field, bigger will be the drift speed.
2. When a steady current flows through a conductor of non-uniform cross-section drift velocity varies inversely with area of cross-section (vd ∝ 1/A)
3. If diameter (d) of a conductor is doubled, then drift speed of electrons under it will not change.
Relaxation time (t)
The time interval between two successive collisions of electrons with the positive ions in the metallic lattice is defined as relaxation time τ = λ/vrms. With rise in temperature v increases consequently t decreases.
Mobility: Drift velocity per unit electric field is called mobility of electron i.e. .μ = vd/E
It's unit is m2/volt-sec.
Email based Physics assignment help - homework help at Expertsmind
Are you searching physics expert for help with Drift velocity questions? Drift velocity topic is not easier to learn without external help? We at www.expertsmind.com offer finest service of Physics assignment help and physics homework help. Live tutors are available for 24x7 hours helping students in their Drift velocity related problems. We provide step by step Drift velocity question's answers with 100% plagiarism free content. We prepare quality content and notes for Drift velocity topic under physics theory and study material. These are avail for subscribed users and they can get advantages anytime.
Why Expertsmind for assignment help
- Higher degree holder and experienced experts network
- Punctuality and responsibility of work
- Quality solution with 100% plagiarism free answers
- Time on Delivery
- Privacy of information and details
- Excellence in solving physics queries in excels and word format.
- Best tutoring assistance 24x7 hours