Why is there a 1/2 instead of 1 in the formula for kinetic energy

In order of decreasing light-transmitting capabilities of materials, which is the correct sequence? a. transparent -> translucent -> opaque b. opaque -> transparent -> translucent c. opaque -> translucent -> transparent d. translucent -> transparent -> opaque

Match each scenario to the form of energy it represents

Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?