PHY2049 - GENERAL PHYSICS II
PRACTICE QUIZ 30

Below you will find a set of 5 conceptual and numerical revision questions selected randomly from lots of questions I have put together covering the material in Chapter 30, "Electromagnetic Waves". This includes questions on the frequency and wavelength of electromagnetic waves, the strength of the E- and B-fields, intensity and radiation pressure. When you have finished the quiz, click on the "Submit Quiz" button at the bottom and within seconds it will be automatically graded and the results returned to you!

To select a new set of questions click on the "Reload" or "Refresh" button on your browser. You may find some of the questions duplicated but that's the nature of a random selection. Try it a few times ... it's not fattening and you may learn something!

Many thanks to Mark Wood for producing the quiz-maker code.


Q1: Arrange the following types of electromagnetic radiation in order of increasing wavelength: gamma rays, infrared light, ultraviolet light, visible light.

Gamma rays are not electromagnetic radiation.
gamma rays, infrared, visible, ultraviolet
gamma rays, ultraviolet, visible, infrared
visible, ultraviolet, infrared, gamma rays
ultraviolet, visible, infrared, gamma rays

Q2: Note the different types of electromagnetic radiation:
(1) X-rays: (2) radio waves: (3) gamma rays: (4) visible light: (5) infrared radiation: (6) ultraviolet radiation
Which list correctly ranks the electromagnetic waves in order of increasing frequency?

2, 3, 4, 5, 6, 1
2, 5, 4, 1, 6, 3
2, 5, 4, 6, 1, 3
3, 1, 6, 4, 5, 2
3, 6, 1, 4, 5, 2.

Q3: A 40 W light bulb emits spherical electromagnetic waves uniformly in all directions. If 45% of the power input to such a light bulb is emitted as electromagnetic radiation, what is the maximum value of the magnetic field at a distance of 3.0 m from the light bulb?

55 × 10-9 T
0.13 × 10-6 T
52 × 10-9 T
89 × 10-9 T
37 × 10-9 T

Q4: The rms value of the electric field in an electromagnetic wave is E(rms) = 200 V/m. The intensity of this wave is approximately

53.1 W/m2
106 W/m2
1.59 × 1010 W/m2
3.18 × 1010 W/m2
1.70 kW/m2

Q5: The figure shows the time variation of the magnitude of the electric field of an electromagnetic wave produced by a wire antenna.

What is the peak value of the magnetic field?

1.4 × 10-8 T
2.3 × 10-8 T
3.3 × 10-8 T
4.6 × 10-8 T
5.4 × 10-8 T


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