That is meters per second, same as velocity.
Answer:
<u>The</u><u> </u><u>best</u><u> </u><u>thermal</u><u> </u><u>insulators</u><u> </u><u>have</u><u> </u><u>free</u><u> </u><u>electrons</u>
I believe it is called an ampere.
Answer:

Explanation:
according to snell's law

refractive index of water n_w is 1.33
refractive index of glass n_g is 1.5


now applying snell's law between air and glass, so we have


![\beta = sin^{-1} [\frac{n_g}{n_a}*sin\alpha]](https://tex.z-dn.net/?f=%5Cbeta%20%3D%20sin%5E%7B-1%7D%20%5B%5Cfrac%7Bn_g%7D%7Bn_a%7D%2Asin%5Calpha%5D)
we know that 
