Chapter 7 Waves
A changing electric field gives rise to
a magnetic field
Ocean waves with a period of 10 s are found to have a wavelength of 120 m. Their speed is
12 m/s
The musical note A has a frequency of 440 Hz and its wavelength in seawater is 3.5 m. The speed of sound in seawater is
1540 m/s
The speed of light in a transparent plastic whose index of refraction is 1.5 is
2 x 10^8 m/s
Radio amateurs are permitted to communicate on the "10-meter band." What frequency of radio waves corresponds to a wavelength of 10 meters? The speed of radio waves is 3 × 108 m/s.
3.0 × 10^7 Hz
Light of which of the following colors has the highest frequency?
blue
Light of which of the following colors is scattered most in the atmosphere?
blue
Of the following, the highest index of refraction is found in
diamond
A converging lens of focal length f produces a real image of a real object when the object is
farther than f from the lens
You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be
less than 1.2 m deep
In a transverse wave, the individual particles of the medium move
perpendicular to the direction of travel
The image the lens of the eye forms on the retina is
real and inverted
An example of a purely longitudinal wave is a
sound wave
The image formed by a diverging lens of a real object is always which of the following?
virtual
A medal in a plastic cube whose index of refraction is 1.5 appears to be 20 mm below the upper surface of the cube. The depth of the medal is actually
30 mm
A boat at anchor is rocked by waves whose crests are 50 m apart and whose speed is 10 m/s. These waves reach the boat once every
5 s
The image a camera lens forms on the film or sensor is
always real
A converging lens of focal length f produces a virtual image of a real object when the object is
closer than f from the lens
The bending of waves around the edge of an obstacle in their path is an example of
diffraction
Ultrasound refers to sound whose
frequency is too high for most people to hear
Relative to its object, a real image formed by a lens is always
inverted
The greater the decibel (dB) level of a sound wave, the
louder it is
In an electromagnetic wave, the electric field is
perpendicular to both the magnetic field and the wave direction
Light of which of the following colors has the longest wavelength?
red
The setting sun appears red because its light is
scattered
Sound waves travel fastest in
solids
Of the following kinds of waves, the ones that cannot travel through a vacuum are
sound waves
An example of a wave that is partly longitudinal and partly transverse is a
water wave
