Which of these describes a wave being reflected?

the wave encounters some obstacle or change in medium. the wave bounces off the surface and moves in a different direction, but at an angle equal to the one at which it hit the surface.

the wave encounters some corner or a small opening. the wave bends and fans out, forming an arc.

two waves move towards each other and the crest of each wave overlaps, creating a new wave that has a greater amplitude than either individual wave.

the wave encounters some change in medium. the wave moves through the new medium in a different direction, but at an equal angle at which it hit the surface.

Suppose that an electromagnetic wave which is linearly polarized along the x−axis is propagating in vacuum along the z−axis. the wave is incident on a conductor which is placed at z > 0 region of the space. the conductor has conductivity σ, magnetic permeability µ and electric permittivity ε. (a) find the characteristic time for the free charge density which dissipates at the conductor. (b) write the maxwell equations and derive the wave equation for a plane wave propagating in a conductor. (c) find the attenuation distance at which the incident amplitude reduces to e ^−1 of its initial value. (d) find the electric and magnetic fields inside the conductor. 8 (e) find the power loss per area of the incident electromagnetic wave at the surface of conductor.

When a light bulb shines, it gives off light energy and energy. a. heat b. potential c. chemical d. electrical

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.