The resistivity of the commercial copper is 1.72 x 10^-8 m. The diameter of a copper wire in the coil of a solenoid is 0.25 mm, and its length is 65 m. Find
a) the resistance of the coil,
b) the heat generated in the coil each second when it is connected to a battery of 1.5 V, (assuming the battery is ideal).