Which term defines the distance from the focal point to either a lens or a mirror?
a. the focal length
b. the polar length
c. the fractal length
d. the resonance length

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final