Which of the following sentences about thermal properties is true?
a. most materials that are good thermal conductors are also good electrical conductors.
b. a material's melting point affects its ability to conduct electricity.
c. specific heat is the rate at which heat flows through a material.
d. thermal conductivity is the rate at which a solid material changes to a liquid.

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?