Deck 7: Waves

Question 1

A sound wave whose frequency is 50 Hz

A) has a relatively short wavelength.
B) has a relatively long wavelength.
C) is very soft.
D) is very loud.

Answer 1

has a relatively long wavelength.

Question 2

The amplitude of the wave shown in the figure is

A) A.
B) B.
C) C.
D) D.

Answer 2

B.

Question 3

A 80-dB sound carries more energy than a 40-dB sound by a factor of

A) 2.
B) 40.
C) 400.
D) 10,000.

Answer 3

10,000.

Question 4

An example of a wave that is partly longitudinal and partly transverse is a

A) sound wave.
B) light wave.
C) water wave.
D) wave in a stretched string.

Question 5

An example of a purely longitudinal wave is a

A) sound wave.
B) light wave.
C) water wave.
D) wave in a stretched string.

Question 6

The greater the decibel dB) level of a sound wave, the

A) higher its frequency is.
B) longer its wavelength is.
C) louder it is.
D) farther away its source is.

Question 7

Which one of the following effects does not occur in all types of wave?

A) reflection
B) polarization
C) diffraction
D) the Doppler effect

Question 8

The wavelength of a sound wave is not related to its

A) pitch.
B) frequency.
C) amplitude.
D) speed.

Question 9

The wavelength of the wave shown in the figure is

A) A.
B) B.
C) C.
D) D.

Question 10

When a sound wave goes from air into water, the quantity that remains unchanged is its

A) speed.
B) amplitude.
C) frequency.
D) wavelength.

Question 11

In a transverse wave, the individual particles of the medium move

A) in circles.
B) in ellipses.
C) parallel to the direction of travel.
D) perpendicular to the direction of travel.

Question 12

The bending of waves around the edge of an obstacle in their path is an example of

A) refraction.
B) reflection.
C) diffraction.
D) the Doppler effect.

Question 13

The higher the frequency of a wave,

A) the lower its speed.
B) the shorter its wavelength.
C) the smaller its amplitude.
D) the lower its pitch.

Question 14

The amplitude of a sound wave determines its

A) loudness.
B) pitch.
C) wavelength.
D) overtones.

Question 15

A pure musical note causes a thin wooden panel nearby to vibrate with the same frequency. This is an example of

A) an overtone.
B) diffraction.
C) interference.
D) resonance.

Question 16

A wave of amplitude A interferes with another wave of the same kind with the same frequency whose amplitude is also

A) has an amplitude of 2A.
B) has an amplitude between 0 and A.
C) has an amplitude between A and 2A.
D) has an amplitude between 0 and 2A.

Question 17

Sound waves travel fastest in

A) a vacuum.
B) gases.
C) liquids.
D) solids.

Question 18

Ultrasound refers to sound whose

A) frequency is too high for most people to hear.
B) wavelength is too long for most people to hear.
C) intensity level is 100 dB or more.
D) frequency has undergone a Doppler shift to a higher one.

Question 19

When waves go from one place to another, they carry

A) amplitude.
B) frequency.
C) wavelength.
D) energy.

Question 20

Two waves meet at a time when one has the instantaneous amplitude A and the other has the instantaneous amplitude

A) A + B.
B) A - B.
C) between A + B and A - B.
D) indeterminate.

Question 21

A frequency that is not an overtone of the fundamental frequency F is

A) F/2.
B) 2F.
C) 3F.
D) 4F.

Question 22

A converging lens of focal length f produces a real image of a real object when the object is

A) closer than f from the lens.
B) at the distance f from the lens.
C) farther than f from the lens.
D) at any distance from the lens.

Question 23

Polarization is similar to

A) refraction.
B) interference.
C) diffraction.
D) None of the choices are correct.

Question 24

In an electromagnetic wave, the electric field is

A) parallel to both the magnetic field and the wave direction.
B) perpendicular to both the magnetic field and the wave direction.
C) parallel to the magnetic field and perpendicular to the wave direction.
D) perpendicular to the magnetic field and parallel to the wave direction.

Question 25

Of the following kinds of waves, those that cannot be polarized are

A) X-rays.
B) radio waves.
C) light waves.
D) sound waves.

Question 26

Which of the following is not a property of an electromagnetic wave?

A) wavelength
B) speed
C) power
D) electric charge

Question 27

You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be

A) less than 1.2 m deep.
B) 1.2 m deep.
C) more than 1.2 m deep.
D) Any of these choices could be correct, depending on the height of the sun.

Question 28

Relative to its object, a real image formed by a lens is always

A) erect.
B) inverted.
C) smaller.
D) larger.

Question 29

Of the following, the highest index of refraction is found in

A) air.
B) water.
C) glass.
D) diamond.

Question 30

The ionosphere

A) reflects radio waves.
B) is responsible for the blue color of the sky.
C) is responsible for rainbows.
D) is caused by the exhausts of high-altitude aircraft.

Question 31

A changing electric field gives rise to

A) a magnetic field.
B) electromagnetic waves.
C) sound waves.
D) nothing in particular.

Question 32

Light of which of the following colors has the longest wavelength?

A) red
B) blue
C) yellow
D) green

Question 33

When a real object is the distance f from a converging lens,

A) the image is virtual, erect, and larger than the object.
B) the image is real, inverted, and larger than the object.
C) the image is real, inverted, and the same size as the object.
D) no image is formed.

Question 34

Of the following kinds of waves, the ones that cannot travel through a vacuum are

A) X-rays.
B) radio waves.
C) light waves.
D) sound waves.

Question 35

A converging lens of focal length f produces a virtual image of a real object when the object is

A) closer than f from the lens.
B) at the distance f from the lens.
C) farther than f from the lens.
D) at any distance from the lens.

Question 36

Light of which of the following colors has the highest frequency?

A) red
B) blue
C) yellow
D) green

Question 37

The image a camera lens forms on the film or sensor is

A) always real.
B) always virtual.
C) sometimes real and sometimes virtual.
D) neither real nor virtual.

Question 38

The image the lens of the eye forms on the retina is

A) real and erect.
B) real and inverted.
C) virtual and erect.
D) virtual and inverted.

Question 39

Relative to the radio signals sent out by a spacecraft headed away from the earth, the signals that are received on the earth have

A) a lower speed.
B) a lower frequency.
C) a shorter wavelength.
D) all of these properties.

Question 40

The image formed by a diverging lens of a real object is always which of the following?

A) virtual
B) real
C) inverted
D) larger than the object

Question 41

The Swedish flag is blue and yellow. When viewed with blue light it appears

A) all blue.
B) blue and yellow.
C) blue and black.
D) white and yellow.

Question 42

Sound waves of frequency 300 Hz have a speed relative to sound waves in the same medium of frequency 600 Hz that is

A) half as great.
B) the same.
C) twice as great.
D) four times as great.

Question 43

Relative to the focal length of a wide-angle camera lens, the focal length of a telephoto lens is

A) shorter.
B) the same.
C) longer.
D) Any of theses choices could be correct, depending on the camera.

Question 44

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

A) 0.2 s.
B) 5 s.
C) 50 s.
D) 500 s.

Question 45

The speed of light in a transparent plastic whose index of refraction is 1.5 is

A) 1.5 × 10⁸ m/s.
B) 2 × 10⁸ m/s.
C) 3 × 10⁸ m/s.
D) 4.5 × 10⁸ m/s.

Question 46

The property of light waves that leads to the phenomenon of color is

A) speed.
B) amplitude.
C) acceleration.
D) frequency.

Question 47

Dispersion is the term used to describe the

A) splitting of white light into its component colors in refraction.
B) propagation of light in straight lines.
C) bending of a beam of light when it goes from one medium to another.
D) bending of a beam of light when it strikes a mirror.

Question 48

Ocean waves with a period is 10 s are found to have a wavelength of 120 m. Their speed is

A) 0.083 m/s.
B) 12 m/s.
C) 120 m/s.
D) 1200 m/s.

Question 49

To an astronaut in orbit around the earth the sky appears

A) red.
B) blue.
C) white.
D) black.

Question 50

The setting sun appears red because its light is

A) refracted.
B) reflected.
C) diffracted.
D) scattered.

Question 51

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

A) 80 m/s.
B) 126 m/s.
C) 1540 m/s.
D) 3 × 10⁸ m/s.

Question 52

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

A) 10 mm.
B) 13 mm.
C) 20 mm.
D) 30 mm.

Question 53

Light of which of the following colors is scattered most in the atmosphere?

A) red
B) blue
C) yellow
D) green

Question 54

When the American flag is viewed with red light it appears

A) all red.
B) red, white, and blue.
C) red and blue.
D) red and black.

Question 55

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.

A) 3.3 × 10^-8 Hz
B) 3.0 × 10⁷ Hz
C) 3.3 × 10⁷ Hz
D) 3.0 × 10⁹ Hz

Question 56

Sound waves of frequency 300 Hz have a wavelength relative to sound waves in the same medium of frequency 600 Hz that is

A) half as great.
B) the same.
C) twice as great.
D) four times as great.