Two light rays A and B travel from a medium into air at angles of incidence 15 degrees and 42 degrees respectively. In the medium, light travels 3 cm in 0.2 ns . Will there be total internal reflection? If so, which ray?

An electric field $E=3 x^2 i N C^{-1}$ exists in a certain region of space. The potential difference between the origin and at $x=4 m, V_0-V_4$ is

A symmetric double convex lens is cut into two equal parts by a plane perpendicular to the principal axis. If the power of the original lens is 4D, the difference between the powers of the original lens and the cut lens is

Three identical conducting balls $\mathrm{A}, \mathrm{B}$ and C , each of mass m , are thrown upward at an angle $\Theta$ to the horizontal with an initial speed $v$ in a region of space that has a uniform electric field $E$ downward along with the gravitational field $g . A$ is positively charged, B is uncharged and C is negatively charged. Rank the ranges R of these three balls in increasing order.