What is the function of a power source in a circuit

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.