Sometimes a board may have an extra pcie power connector. this connector comes in what two different pin numbers?

Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude f due to the other. with time, charge gradually leaks off of both spheres. when each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

What object a collides with object b and bounces back its final momentum is?