7) A ray of light incident normally on one of the face of a prism of angle 30°. The value of first refracted angle r, is
(a)26° b) o c) 60' d) 30°

Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude f due to the other. with time, charge gradually leaks off of both spheres. when each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be

Who was the first scientist to measure speed as distance over time?

1. how to locate the image in converging(concave) mirror and diverging (convex) mirror with salt. 2. how to locate the image in a converging (convex) lens and diverging (concave) lens with salt.