please tell me if thsi si correct

Two equal charges are separated by 3.7 * 10^-10 m. the force between the charges has a magnitude of 2.37 * 10^-3 N. What is the magnitude of q on the changes?

f=1/4pi Er * q^2/r^2

2.37 * 10^-3 = 9*10^9 * q^2
______________
(3.7 * 10^-10)^2

3.61 * 10^-32= q^2
q= 1.8 * 10^-16
is that correct?

What is the resistance of a resistor if the potential difference across the resistor is 4.0 V when a current of 10.0 A flows through the resistor?

R=V/I= 4/10

R=0.4 ohms

is this done correctly

thanks