*help FAST* !15 pts! What is needed to build a laser?

A. a concave lens and a convex lens that are fully reflective.
B. Two partially reflective mirrors
C. Two fully reflective mirrors
D. A partially reflective mirror and a fully relfective mirror.

Alinearly polarized electromagnetic wave has an average intensity of 196 w/m^2. this wave is directed towards two ideal polarizers (in real polarizers, transmission is also effected by reflection and absorption). polarizer a is oriented with its transmission axis at an angle of θ_1=20.8∘ with the incident electric field. polarizer b has its axis at an angle of θ_2=63.0∘ with the incident electric field. what is the average intensity of the wave after it passes through polarizer a? what is the average intensity of the wave after it passes through polarizer b? suppose that the two polarizers a and b are interchanged. what would the average intensity be after passing through both polarizers?

A17,250 kg rocket is pushed with a thrust of 6,450,284 n. what is the acceleration of the rocket?

What determines the amount of inertia an object has