Sound 4

Why sound cannot be heard in a vacuum?

• Sound is a form of light that cannot penetrate a vacuum.
• Sound cannot be heard in a vacuum because there is no medium for it to travel through.
• Sound can travel faster in a vacuum than in air.
• Sound waves are absorbed by the vacuum, preventing them from being heard.

How to make a sound?

• Musical instruments

• Singing in a vacuum

• Closing the mouth

• Shouting in a vacuum

Mention parts of ears!

• ear canal, pinna, ossicles, cochlea, nerves

• auditory canal, iris, pupil, retina, lens

• cochlear, cornea, iris, retina, sclera

• eardrum, cochlear, cornea, iris, retina, sclera

How much time does it take, when the motorcycle has a speed of 10 m/s to reach a distance of 1.2 km?

• 60 seconds
• 180 seconds
• 120 seconds
• 240 seconds

How much speed of sound in air ?

• 300 meters per second
• 400 meters per second
• 250 meters per second
• 340 meters per second

Calculate the speed of sound, when the car moves to travel 7 km in 30 minutes!

• 8 km/h

• 7 km/h

• 12 km/h

• 14 km/h

The pitch depends on.....

• frequency
• timbre
• wavelength
• amplitude

What is the Doppler Effect?

• The Doppler Effect is the phenomenon where sound waves become louder as they approach the observer.
• The Doppler Effect is the change in frequency of sound waves due to the relative motion between the source and observer

• The Doppler Effect is the increase in amplitude of a wave due to the observer's motion.
• The Doppler Effect refers to the change in color of an object due to its temperature.

The second resonance of the turning fork occurs in the air space 20 cm high tube. If the speed of sound propagation in air is 340 m/s. What is the period of the turning fork?

• 0.00078 seconds

• 0.0089 seconds

• 0.00058 seconds

• 0.0027 seconds

Examples animals can hear ultrasound over are....

• Turtles, dogs

• Goldfish, bats

• bats, dolphins

• Rabbits, bats