If a battery is running down, a light bulb in the circuit will become dimmer because when voltage drops
a. there's less current flowing through the bulb.
b. the resistance in the circuit increases proportionally.
c. the circuit that was once closed is starting to open some.
d. there's the same amount of current flowing but it's not flowing as fast.

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

Agas initially at p1 = 1 bar and occupying a volume of 0.5 liter is compressed within a piston–cylinder assembly to a final pressure p2 = 4 bar. (a) if the relationship between pressure and volume during the compression is pv = constant, determine the volume, in liters, at a pressure of 3 bar. (b) repeat for a linear pressure–volume relationship between the same end states. reference

Because light travels in a straight line and casts a shadow, isaac newton hypothesized that light is