Jin listed some common thermal insulators and conductors in a chart.
which belongs in the area marked with an x?
a iron
b foam
c wood
d glass

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples