1- a cylindrical resistor of radius 1.0 mm and length of 1.0 cm has resistance of 10 ohms. calculate the uniform current density in the resistor when the power of the resistor is 1 watt?
2- a cylindrical resistor of radius 5.0 mm and length 2.0 cm is made of material that has a resistivity of 3*10^-5 ?·m at 20 C and a temperature coefficient of resistivity of 4*10^-3 k^-1. calculate the resistance of the resistor at 440 C?