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