GT Sound and Light Waves with Explanation

What is pitch?

• The rate at which a vibration occurs

• The distance between successive crests of a wave

• The degree of highness or lowness of a tone

• Vibrations that travel through the air or medium

Answer explanation

Pitch refers to the degree of highness or lowness of a tone. This is determined by the frequency of sound waves. So, in the given question, the most accurate answer is 'The degree of highness or lowness of a tone'. The other options refer to different aspects of sound but not specifically to pitch.

What is frequency?

• The rate at which a vibration occurs

• The distance between successive crests of a wave

• The degree of highness or lowness of a tone

• Vibrations that travel through the air or medium

Answer explanation

Frequency refers to the rate at which vibration occurs in a cycle and not related to the distance between wave crests or the degree of tone. It also has nothing to do with the mode of vibration travel. Thus, the correct answer is 'The rate at which a vibration occurs'.

What is wavelength?

• The rate at which a vibration occurs

• The distance between successive crests of a wave

• The degree of highness or lowness of a tone

• Vibrations that travel through the air or medium

Answer explanation

The question is asking about the definition of 'wavelength'. The correct option is the one stating 'The distance between successive crests of a wave'. Wavelength specifically refers to the distance between one wave peak to the next, not the rate of vibrations, the degree of a tone's highness or lowness, or the existence of vibrations traveling through a medium.

Tags

NGSS.MS-PS4-1

NGSS.MS-PS4-2

What is sound?

• The rate at which a vibration occurs

• The distance between successive crests of a wave

• The degree of highness or lowness of a tone

• Vibrations that travel through the air or medium

Answer explanation

Sound is a form of energy that's produced when things vibrate. This vibration creates sound waves which move through mediums such as air, water, or metal. So, the correct answer to the question 'What is sound?' is 'Vibrations that travel through the air or medium'. The other options don't correctly define sound.

What is volume?

• The rate at which a vibration occurs

• The distance between successive crests of a wave

• The degree of highness or lowness of a tone

• The quantity or power of sound; degree of loudness

Answer explanation

The correct answer is 'The quantity or power of sound; degree of loudness'. The term 'volume' in physics is used to refer to the magnitude or intensity of sound. It is not related to the rate of vibration, distance between wave crests, or the pitch of a tone, which are associated with frequency, wavelength, and pitch respectively. Therefore, the correct answer is associated with the loudness or power of the sound.

When the car moves AWAY from you, its horn seems...

• Low pitched

• High pitched

• Normal

Answer explanation

This question is based on the Doppler Effect, which states that a change in frequency of a wave in relation to an observer moving relative to the source of the wave. When a car is moving away from you, the sound waves from the horn are stretched out, which make them vibrate at a lower frequency. Therefore, the horn seems 'Low pitched', which is the correct answer.

Tags

NGSS.MS-PS4-1

When an ambulance move TOWARD you it sounds ________ pitched. 

• high

• low

• medium

Answer explanation

The question asks about the pitch of the sound an ambulance makes when it moves toward you. The correct answer is 'high'. This is because of the Doppler Effect - as the ambulance moves towards you, the sound waves get compressed leading to a higher pitch sound.

Tags

NGSS.MS-PS4-1

NGSS.MS-PS4-2

The Doppler effect is seen when a wave-making source moves toward an observer. 

• True

• False

Answer explanation

True. The Doppler effect, named after Christian Doppler, is observed when a wave-making source, like light or sound, moves towards or away from an observer. When the source moves towards the observer, the waves are compressed, which in case of sound, results in a higher pitch. Thus, when a wave-making source moves towards an observer, the Doppler effect is clearly observed.

Tags

NGSS.MS-PS4-1

What can you tell about this object's motion?

• Moving to the North (up).

• Moving to the South (down). 

• Moving to the West (left). 

• Moving to the East (right). 

Answer explanation

The correct choice is 'Moving to the East (right)'. This option was chosen because the object's motion is described as going right, which corresponds to the direction east. The other options, moving up, down, or left, did not match the direction implied by the question.

What can you tell about the motion of this object?

• Moving left.

• Moving right quickly.

• Standing still. 

• Moving up slowly. 

Answer explanation

The correct response to the question 'What can you tell about the motion of this object?' is 'Standing still.'. This option is selected because it correctly describes the state of the object's motion among all the given options. The object is not moving in any direction, hence it's in a stationary state.