Question

state the laws of reflection and describe an experiment to verify them

Answer 1

You're doing an experiment to verify a law, so you start with stating the laws:

For a reflective surface, the angle of reflection, relative to the surface normal (the line perpendicular to the surface at that point), is the same as the angle of incidence.For a refracting surface, we're talking Snell's Law - index of refraction of media 1  times the sine of the angle of incidence is equal to index of refraction of media 2 times the sine of the transmission angle (angles measured from the normal of the boundary between the media.

You then will show how you will:

Measure the angle of incidence  and the angle of reflection for the reflection.What angle or angles you will use - a good experiment will make more than one measurement, and will cover a wide range of angles to show that the law works over the expected range, which in this case should be 0 to 90 degrees.Deal with extreme cases - how to tell where your light hits when it's almost parallel to the mirror, how to distinguish incident light from reflected light if the angle is zero, or close to it.Measure the incidence and transmission angles for refraction, especially if one of the media is liquid or solid.  Will you look for beam scatter? Will you look for where the beam emerges from media 2 and do some trigonometry?How will you find the indices of refraction for the different media? Or will you reverse the experiment, perhaps, assume the law works, and then calculate the indices of refraction (or at least their ratio) from a series of measurements.For a good experiment, as a baseline, you'll also describe the uncertainty of your observations, any statistics used, any data excluded (and why), and your method of deriving answers - are you using inverse sine functions? Are you using small angle approximations? Did you process your data so you could use a nice least-squares fit?

Answer 2

Laws of reflection

i) The normal ray,the reflected ray and normal all lie in same plane.
ii) The angle of incidence is always equal to angle of reflection.
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