What is difference between current and drift velocity?
Current is the flow of free charges, such as electrons and ions. Drift velocity vd is the average speed at which these charges move.
What is the relation between drift velocity and area?
Current IenA=v where v is drift velocity , e is the charge of an electron, n is no of electrons per unit volume and A is area of cross section.
How is the electron drift velocity affected if radius r is doubled?
The radius r is doubled. The drift velocity is independent of the radius of the conductor. So the drift velocity will not be affected.
What happens when current is passed through a copper wire?
When current flows through a conductor such as a copper wire, all of those electrons that were previously moving about randomly get together and start moving in the same direction. The result is that even though the individual electrons move slowly, the current itself moves at nearly the speed of light.
What is the average drift velocity of the electrons in this copper wire?
The current developed due to this drift movement of electrons under the influence of an external field is called drift current and the velocity is termed as drift velocity. Where e=1.6×10−19C is the charge of electrons. Therefore the required drift velocity is 0.00104m/s or 1.04×10−3m/s.
When a 5V potential difference is applied?
When 5V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5 × 10–4 ms–1. If the electron density in the wire is 8 × 1028 m–3, the resistivity of the material is close to: 1.6 x 10-8Ωm. 1.6 x 10-7Ωm.
What is the average drift speed of the electrons along the wire?
10-4 m/s.
Why do electrons acquire a steady drift velocity?
Electron gains kinetic energy. During movement, electrons collide with other accelerated electron and atom, so they loss kinetic energy. Hence, they cannot accelerate continuously, so they move with steady average drift velocity.
Why is current not established in absence of electric field?
Electrons move in all directions haphazardly in metals. When an electric field is applied, each free electron acquire a drift velocity. There is a net flow of charge, which constitute current. In the absence of electric field this is impossible and hence, there is no current.
Why is there no current established in a conductor in the absence of electric field although a large number of free electrons are moving with high speed?
In the absence of electric field, the free electrons in the metal have random motions. During motion, they collide with positive ions of the metal again and again and after each collision, their direction changes. So, there is no net flow of charge carries in a particular direction and hence no current flows.
Are electrons moving in metals?
Metals contain free moving delocalized electrons. When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor. Electrons will move toward the positive side.
Why do we use connecting wires made of copper?
Copper electrical wires are safer to use than wires made of most other conductive metals because they are resistant to heat. As you can see, copper is the preferred metal for electrical wires for several reasons. It has high electrical conductive; it’s inexpensive; it’s ductile; and it’s thermal resistant.
Why is that electrons carry current in metals?
Flow of current in metals is due to preferential flow of free electrons. In the absence of any externally applied emf (by means of a battery), the free electrons move randomly through the metal from one point to another giving zero net current.