When an object is between the focal point and a concave mirror, so is negative. What other values must be negative for your equations to still work?

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?

The energy released by a nuclear fusion reaction is produced when

Current from a charged capacitor lights a bulb. as time goes on the brightness of the