A.) Calculate the power dissipated in the 2 Ω resistor, if the voltage of the battarey is ε=21.2 V and the resistance of the resistor is R=8.7 Ohms? Express the answer to two decimal places.
B.) Find the resistance of a 21 meter length of metal wire of 0.5 mm diameter. The resistivity of metal is 1.4×10-6 Ω·cm at a temperature of 20°C. Express the answer with two decimal places.