Both systems send out waves (sound waves in water and electromagnetic waves in air, respectively) and record the time it takes for the reflections to arrive back. This is the sound underneath the dome of a mosque in Iran.Įchoes are used in Sonar and Radar. The problem is even worse when there is a curved surface.
Diffusers could also help the problem by dispersing the reflection causing the echo. To overcome this problem, absorbers can be put on the rear wall to stop the sound reflecting, as was done in the Royal Festival Hall, London shown below. Sometimes this sound can be heard by the audience as an echo. If a trumpet plays on the stage, the sound can reflect off the back wall and return to the front of the seating (stalls) still quite loud.
The constant value is known as refractive index of medium in which refraction is takes place.The laws of reflection are the same for all types of waves, including light and sound. Difference between Laws of reflection and refraction Laws of reflectionġ) The bouncing back of rays of light when it falls on optically opaque surface is known as reflection of light.Ģ) In reflection, incident ray and reflected ray follows certain path, gives rise to laws of reflection, refer the following fig.ģ) First law states that, incident ray and reflected ray lies on opposite sides of normal, and all three (incident ray, reflected ray and normal) lies in same plane at the point of incidence.Ĥ) Second law states that, angle of incidence is equal to angle of reflection.ĥ) Angle of incidence, ∠i = angle of reflection, ∠r Laws of refractionġ) The change in the direction of light when it passes from one transparent medium to another is called as refraction of light.Ģ) In refraction, incident ray and reflected ray follows certain path, gives rise to laws of refraction, refer the following fig.ģ) First law states that, incident ray and refracted ray lies on opposite sides of normal, and all three (incident ray, reflected ray and normal) lies in same plane at the point of incidence.Ĥ) Second law states that, the ratio of sine of angle of incidence to angle of refraction is constant for given pair of media.ĥ) Angle of incidence,∠i α angle of reflection,∠r