chapter 26 Flashcards
(15 cards)
Electromagnetic waves are composed of _________.
electric and magnetic fields
An electric field is induced by ______________.
a changing magnetic field
The electromagnetic waves having the highest speed in free space are _________.
none in particular as gamma, radio, and light have the same speed
What would happen if light was moving at a lower speed?
Energy would be lost and none would be transported from one place to another.
How is the fact that an electromagnetic wave in space never speeds up consistent with the law of conservation of energy?
If light speeded up, its energy would increase, thereby violating the law of conservation of energy.
How do the wavelength and frequency of infrared light compare to the wavelength and frequency of ultraviolet light?
The wavelength of infrared is larger than that of ultraviolet, and the frequency is smaller.
How does frequency change when wavelength is increased?
The frequency decreases.
How does the speed of radio waves compare with the speed of gamma rays?
The speed of radio waves is equal to the speed of gamma rays.
An electromagnetic wave is propagating in the positive x direction. At a given moment in time, the magnetic field at the origin points in the positive y direction. In what direction does the electric field at the origin point at that same moment?
F. Negative z
The figure shows the electromagnetic field as a function of position for two electromagnetic waves traveling in a vacuum at a given moment. Which statement about the frequency and speed of the waves is correct?
A. The frequency of wave A is greater than that of wave B, but the speeds of the two waves are the same.
At a given location in space, the magnetic field in an electromagnetic wave is increasing. How is the electric field changing at that same location?
The electric field is increasing.
Rank the following types of electromagnetic waves by the wavelength of the wave.
Visible light & X-rays, Microwaves, Radio wave
Longest to shortest:
1. Radio waves
2. Microwaves
3. Visible light
4. X-rays
The smallest portion of the electromagnetic spectrum is _________.
visible light
How does the speed of an electromagnetic wave change with frequency?
All electromagnetic waves move at the same speed in a vacuum.
How is the wavelength of light related to its frequency?
The wavelength is inversely proportional to the frequency.
