Assume the helium-neon lasers commonly used in student physics laboratories have power outputs of 0.35 mW. P = 0.35 mW d = 1.8 mm   (a)  If such a laser beam is projected onto a circular spot 1.8 mm in diameter, what is its intensity in W/m2?  (b)  Find the peak magnetic field strength in T.  c) Find the peak electric field strength in V/m.

A radio station broadcasts at a frequency of 760 kHz. At a receiver some distance from the antenna, the maximum magnetic field of the electromagnetic wave detected is 2.151011T . (a) What is the maximum electric field? (b) What is the wavelength of the electromagnetic wave?

A parallel-plate capacitor with plate separation d is connected to a source of emf that places a time-dependent voltage V(t) across its circular plates of radius r0and area (a) Write an expression for the time rate of change of energy inside the capacitor in terms of V(t) and dV(t)/ dt. (b) Assuming that V(t) is increasing with time, identify the directions of the elecuic field lines inside the capacitor and of the magnetic field lines at the edge of the region between the plates, and then the direction of the Poynting vector S at this location. (c) Obtain expressions for the time dependence of E(t), for B(t) from the displacement current, and for the magnitude of the Poynting vector at the edge of the region between the plates. (d) From S , obtain an expression In terms of ‘(t) and dV(t)/dt for the rate at which electromagnetic field energy the region between the plates. (e) Compare the results of pails (a) and (d) and explain the relationship between them.

If the electric field of an electromagnetic wave is oscillating along the z-axis and the magnetic field is oscillating along the x-axis, in what possible direction is the wave traveling?

Assume the helium-neon lasers commonly used in student physics laboratories have power outputs of 0.500 mW. (a) If such a laser beam is projected onto a circular spot 1.00 mm in diameter, what Is its Intensity? (b) Find the peak magnetic field strength. (C) Find the peak electric field strength.

Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1,00 W/m2. (a) If a radar unit leaks 10.0 W of microwaves (other than those sent by its antenna) uniformly in all directions, how far away must you be to be exposed to an intensity considered to be safe? Assume that the power spreads uniformly over the area of a sphere with no complications from absorption or reflection, (b) What is the maximum electric field strength at the safe intensity? (Note that early radar units leaked more than modem ones do. This caused identifiable health problems, such as cataracts, for people who worked near them.)

A certain 60.0-Hz ac power line radiates an electromagnetic wave having a maximum electric field strength of 13.0 kV/m. (a) What is the wavelength of this very-low-frequency electromagnetic wave? (b) What type of electromagnetic radiation is this wave (b) What is its maximum magnetic field strength?

What is the maximum electric field strength in an electromagnetic wave that has a maximum magnetic field strength of 5.00104 (about 10 times Earth's magnetic field)?

A small helium-neon laser has a power output of 2.5 mW What is the electromagnetic energy in a 1.0-m length of the beam?

An electron in a TV CRT moves with a speed of 6.0107 m/s, in a direction perpendicular to Earth's field, which has a strength of 5.0105 T. (a) What strength electric field must be applied perpendicular to the Earth’s field to make the election moves in a straight line? (b) If this is done between plates separated by 1.00 cm, what is the voltage applied? (Note that TVs are usually surrounded by a ferromagnetic material to shield against external magnetic fields and avoid the need for such a collection,)