A proton of mass m and electric charge q enters a region of magnetic field at point P and exits at point Q. The speed of the proton at P is v. The path followed by the proton is a quarter of a circle.
(a)
State and explain whether the speed of the proton at P is the same as the speed at Q.
The diagram shows two parallel plates. The electric field between them is directed from top to bottom and has a magnitude 2.6 × 103 N C–1. The shaded region is a region of magnetic field normal to the page.
(b)
Deduce the magnetic field magnitude and direction so that an electron experiences zero net force when travelling through the plates with a speed of 3.0 × 105 ms–1.
A taut electrical wire carries electricity between a generator and the step-up transformer. The current is 2000 A and the magnetic field of the Earth at the position of the wire is 4.50 × 10–5 T and makes an angle of 45⁰ below the horizontal.
(d)
Calculate the force experienced by a 25.0 m length of this wire.
A current I passes through a conductor. The electrons move with a drift speed v. A magnetic field B at right angles to the direction of motion of the electrons is also present in the conductor.
(a)
Draw the arrows to indicate the directions of the:
A is the cross-sectional area of the conductor, q is the charge of one electron, n is the number of electrons per unit volume and v is the drift speed of the electrons.
(b)
Show that the current on the conductor is given by I = qnAv.
, where B is the magnetic flux density.
