Doppler effects

What is the Doppler effect?

• The observed change in frequency of sound or light because of the relative motion of a wave source and the observer.

• The observed change in amplitude of sound or light because of the relative motion of a wave source and the observer.

• The observed change in wave speed of sound or light because of the relative motion of a wave source and the observer.

• The observed change in equilibrium position of sound or light because of the relative motion of a wave source and the observer.

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-5

You stand on the sidewalk next to the street. A fire truck is moving towards you. The frequency of the siren on the fire truck is 600 Hz.

What should you hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

Tags

NGSS.HS-PS4-1

You stand on the sidewalk next to the street. A fire truck is away from you. The frequency of the siren on the fire truck is 600 Hz.

What should you hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

Tags

NGSS.HS-PS4-1

You stand on the sidewalk next to the street. A fire truck is away from you. The frequency of the siren on the fire truck is 600 Hz.

What should the firemen on the truck hear?

• Frequency higher than 600 Hz

• Frequency lower than 600 Hz

• Exactly 600 Hz

• No sound, silence.

Tags

NGSS.HS-PS4-1

Which situation will result in the highest observed frequency?

• Observer moves at 20 m/s towards sound source.

  Sound source is motionless.

• Observer moves at 20 m/s towards sound source.

  Sound source moves at 20 m/s towards the observer.

• Observer is motionless.

  Sound source moves at 20 m/s towards the observer.

• Observer is motionless.

  Sound source moves 20 m/s away from the observer.

Tags

NGSS.HS-PS4-1

Which situation will result in the lowest observed frequency?

• Observer moves at 20 m/s towards sound source.

  Sound source is motionless.

• Observer moves at 20 m/s towards sound source.

  Sound source moves at 20 m/s towards the observer.

• Observer is motionless.

  Sound source moves at 20 m/s towards the observer.

• Observer is motionless.

  Sound source moves 20 m/s away from the observer.

Tags

NGSS.HS-PS4-1

A car moves at 20 m/s towards a whistle. The whistle is stationary. The whistle makes a sound with a frequency of 500 Hz. The speed of sound in air is 330 m/s.

What is the frequency observed by the driver of the car?

• 530 Hz

• 470 Hz

• 520 Hz

• 480 Hz

Tags

NGSS.HS-PS4-1

A car moves at 20 m/s away from a whistle. The whistle is stationary. The whistle makes a sound with a frequency of 500 Hz. The speed of sound in air is 330 m/s.

What is the frequency observed by the driver of the car?

• 530 Hz

• 470 Hz

• 520 Hz

• 480 Hz

Tags

NGSS.HS-PS4-1

You look at a star through a telescope. You use a special camera to measure the light being emitted from the star. The star should be a blue color, but it appears to be slightly purple.

What is the star doing?

• Moving away from the Earth.

• Moving towards the Earth.

• Motionless in space.

• Shrinking in size.

Tags

NGSS.HS-ESS1-2

NGSS.HS-PS4-1

You look at a star through a telescope. You use a special camera to measure the light being emitted from the star. The star should be a yellow color, but it appears to be slightly orange.

What is the star doing?

• Moving away from the Earth.

• Moving towards the Earth.

• Motionless in space.

• Shrinking in size.

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3