Physics U24, U25, U26 Important

Motor Effect: A current-carrying conductor has a magnetic field around it. This field interacts with the magnet's magnetic field and produces a force according to Fleming's Left Hand Rule.

• So the wire experiences a force inside the page.
• Using Newton's Third Law, the magnet experiences a force outside the plane of the page.

F = B x I x L

F = B x I x L Sin theta

F = B x (Q/t) x L Sin theta

F = B x Q x v Sin theta (when the charge is moving without any conductor)

F = B x e x v Sin theta 

e = elementary charge = 1.6 x 10^(-19) C

Q = charge of protons or electrons

B = Magnetic Flux Density

I = Conventional Current

L = Length of conductor inside the magnetic field.

FB is uniform. (B is inside the page)

FB is perpendicular to velocity

FB = FCP

B e v sin theta = m v^2 / r

B e sin theta = m v / r

The electric field is perpendicular to the magnetic field. The velocity of the charged particle is perpendicular to both electric and magnetic fields. Both these forces are equal and cancel out for particles moving at a specific velocity. Given by: v = E/B

Fe = FB

E q = B q v

E = B v

v = E / B

VH = (B x I) / (n x t x e) = Hall Voltage

Magnetic field strength is inversely proportional to the square separation, which is known as the Inverse Square Law.

1. If mass of charge rises or charge rises, then velocity decreases.
2. But if velocity rises, then PB = qv rises. The q will deviate the direction of FB.

Magnetic Flux

SI unit: Weber (Wb)

It is the measure of the total magnetic field passing through a given surface.

= B x A cos theta

B = magnetic flux density (Number of field lines passing through unit area)

A = Area of the surface of the coil 

theta = Angle between the normal to Area vector and magnetic field. (Angle between magnetic field and the normal perpendicular to the surface.)

Faraday's Law: In a closed circuit, magnitude of induced emf is directly proportional to the rate of change of magnetic flux linkage through the circuit.

Lenz's Law: Direction of induced electromagnet force in a conductor such that it opposes the change in magnetic flux that produced it.