Describe and explain how sound travels in each: Solids: Liquids: Gas: Outer Space: List an example for each kind of energy transfer: Thermal to electrical: Electrical to mechanical: Mechanical to sound: Electrical to light: Define and give an example of each term as it relates to light: Reflection: Refraction: Absorption: Lens: Define each term as it relates to electricity: Open circuit: Closed Circuit: Solution 1) Sound travels in different forms in different medium Solids: In solids, sound waves travel as both longitudinal as well as transverse waves. Longitudinal waves are alternate regions of compressions and rarefractions caused by pressure deviations from the mean pressure. On the other hand, transverse waves are caused by alternate regions of shear stress developed perpendicular to the direction of propogation of the sound wave. Liquids: In liquids, sound travels through alterante regions of high pressure(compression) and low pressure(rarefraction). Such type of waves are known as longitudinal waves. The source causing the sound vibrates, thus compressing and expanding the air in the region near the source. This gets propogated in space through longitudinal waves. Gasses: Like in liquids, sound travels through through longitudinal waves in gasses too.. The source causing the sound vibrates, thus compressing and expanding the air in the region near the source. This gets propogated in space through longitudinal waves. Outer Space: Sound requires some medium for propogation. Since outer space is devoid of any matter, sound does not travel in outer space. 2) Thermal to Electrical: Thermoelectric generators, Thermocouples etc Electrical to Mechanical: AC Generator Mechanical to sound: Bells, Percussion Instruments Electrical to light: Torch light, Light Bulbs 3) Reflection: The change in direction of light wave on hitting a surface is known as reflection. Eg: Mirror Refraction: Bending of light wave as it travels from one medium to another is known as refration. refraction mainly happens due to difference in the refractive index between to the two mediums. Eg: Contact lens, lens in microscopes Absorption: The phenomenon by which light wave could be absorbed by a material when incident on it is known as absorption. Eg: Absorption of light by chlorophyl for photosynthesis Lens: lens is an optical device that bends light in a required fassion through refraction. depending on the requirement and the shape of the lens, it can be used to focus the light beam or disperse. Eg: Contact lens 4) Open circuit: An electrical circuit without a complete path between the terminals of the power source is known as open circuit Closed circuit: An electrical circuit with atleast one complete path between the terminals of the power source is known as open circuit.

1. Describe and explain how sound travels in each: Solids: Liquids: Gas: Outer Space: List an
example for each kind of energy transfer: Thermal to electrical: Electrical to mechanical:
Mechanical to sound: Electrical to light: Define and give an example of each term as it relates
to light: Reflection: Refraction: Absorption: Lens: Define each term as it relates to electricity:
Open circuit: Closed Circuit:
Solution
1) Sound travels in different forms in different medium
Solids:
In solids, sound waves travel as both longitudinal as well as transverse waves. Longitudinal
waves are alternate regions of compressions and rarefractions caused by pressure deviations from
the mean pressure. On the other hand, transverse waves are caused by alternate regions of shear
stress developed perpendicular to the direction of propogation of the sound wave.
Liquids:
In liquids, sound travels through alterante regions of high pressure(compression) and low
pressure(rarefraction). Such type of waves are known as longitudinal waves. The source causing
the sound vibrates, thus compressing and expanding the air in the region near the source. This
gets propogated in space through longitudinal waves.
Gasses:
Like in liquids, sound travels through through longitudinal waves in gasses too.. The source
causing the sound vibrates, thus compressing and expanding the air in the region near the source.
This gets propogated in space through longitudinal waves.
Outer Space:
Sound requires some medium for propogation. Since outer space is devoid of any matter, sound
does not travel in outer space.
2)
Thermal to Electrical: Thermoelectric generators, Thermocouples etc
Electrical to Mechanical: AC Generator
Mechanical to sound: Bells, Percussion Instruments
Electrical to light: Torch light, Light Bulbs
3)
Reflection: The change in direction of light wave on hitting a surface is known as reflection. Eg:
Mirror
Refraction: Bending of light wave as it travels from one medium to another is known as
refration. refraction mainly happens due to difference in the refractive index between to the two

2. mediums. Eg: Contact lens, lens in microscopes
Absorption: The phenomenon by which light wave could be absorbed by a material when
incident on it is known as absorption. Eg: Absorption of light by chlorophyl for photosynthesis
Lens: lens is an optical device that bends light in a required fassion through refraction. depending
on the requirement and the shape of the lens, it can be used to focus the light beam or disperse.
Eg: Contact lens
4)
Open circuit: An electrical circuit without a complete path between the terminals of the power
source is known as open circuit
Closed circuit: An electrical circuit with atleast one complete path between the terminals of the
power source is known as open circuit