Electricity and Magnetism Answers

In a certain particle accelerator, electrons emerge with an energy of 40.0 MeV (1 MeV=

1.60 X 10-13 J). The electrons do not emerge as a steady stream but rather in pulses at the

rate of 250 pulses/s. This corresponds to a time interval between pulses of 4.00 ms (See

figure 5). Each pulse has duration of 200 ms, and the electrons in the pulse constitute a

current of 250mA. The current is zero between pulses

a) How many electrons are delivered by the accelerator per pulse?

b) What is the average current per pulse delivered by the accelerator?

c) What is the peak power delivered by the electron beam?

Two semiconductor materials have exactly the same properties except that material A has a

bandgap energy of 1.0 eV and material B has a bandgap energy of 1.2 eV. Determine the ratio

of ni, of material A to that of material B for T = 300 K.

A sphere has an excess of 2,88 x 1013 electrons. What is the charge on the sphere?

A square coil is placed in a magnetic field. The coil is composed of 450 turns of wire. As the coil is wound around, the magnetic field changes at a constant tempo from 0,2 T to 0,42 T in 6 x 10-2 seconds. The induced emf is – 15 V.

1. Calculate the change in magnetic flux in the coil.
2. Calculate the length of the side of the coil

If a vector A = ax + 2a y + 3az , find its magnitude and direction