Post test : Sound Wave

Sound waves are longitudinal wave

• True
• False

Sound can travel through solids, liquids and gases, but cannot travel though vacuum.

• True
• False

What is the factor to increase the speed of sound?

• Air Pressure
• Temperature
• Volume of air
• No. of particle 

Why sound can travel more faster in solids and liquids than in a gases?

• Particles cannot move freely.
• Kinetic energy of particles low.
• Distance between particles is closer.
• Particles do not touch each other.

Which answer is false?

• Sound can be reflected.
• Sound is a mechanical wave.
• Sound can travel though a gases. 
• Sound cannot be diffracted

State the Law of Reflection.

• r is greater than i
• i is greater than r
• Incident angle, reflected angle and normal lie on the same plane.

Which characteristics of reflection is false?

• Direction of the propagation of waves changes after undergoing reflection.
• Angle of incident equal to angle of reflection.
• The wavelength and frequency of the reflected waves is the same as the incident waves.
• The speed of reflected waves is difference with incident waves.

What is the effect of sound wave at night?

• The layer of air close to the ground is hotter than that above it.
• A person hears the sound louder at night.
• Sound travels slower in warm air than in cool air.
• More sound is refracted away from the ground. 

Police and ambulance  sirens use sound of ....

• Low energy
• Low wavelenght
• Low frequency
• High speed

The range of normal person able to hear is called

• Infrasound
• Ultrasound
• Audible frequency