When an electron is displaced in a semiconductor, the hole that's left behind is

a. attracted to the negative terminal of the voltage source.
b. incapable of carrying a charge.
c. attracted to the anode of the voltage source.
d. considered an impurity in the crystal.

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.

The energy of a photon is equal to (what) times (what) of the photon.

If a person whirls an object horizontally in a counter clockwise direction and the string breaks at point p as shown, what path will the rock follow?