PHY102: Electricity and Magnetism

Homework 4

PART-A

Q1. A toroid having a rectangular cross section (a = 2.00 cm by b = 3.00 cm) and inner radius R

= 4.00 cm consists of 500 turns of wire that carries a sinusoidal current I = I max sin ωt, with

Imax= 50.0 A and a frequency f =ω/2π= 60.0 Hz. A coil that consists of 20 turns of wire links

with the toroid, as in Figure. Determine the emf induced in the coil as a function of time.

Q2In Figure , the bar magnet is moved toward the loop. Is Va – Vb positive, negative, or zero?

Explain..

Q3A coil of area 0.100 m2 is rotating at 60.0 rev/s with the axis of rotation perpendicular to a

0.200-T magnetic field. (a) If the coil has 1 000 turns, what is the maximum emf generated in it?

(b) What is the orientation of the coil with respect to the magnetic field when the maximum

induced voltage occurs?

Part-B

Q4 .An electron moves through a uniform electric field E = (2.50iˆ +2 5.00jˆ) V/m and a uniform

magnetic field B =(0.400kˆ)T. Determine the acceleration of the electron when it has a velocity v

=10.0iˆ m/s.

Q5 What is the average magnitude of the Poynting vector 5.00 miles from a radio transmitter

broadcasting isotropically with an average power of 250 kW?

Q6 In SI units, the electric field in an electromagnetic wave is described by

Find (a) the amplitude of the corresponding magnetic field oscillations, (b) the wavelength λand

(c) the frequency f.