A heating element is made by maintaining a potential difference of 68.0 V across the length of a Nichrome wire that has a 3.01 × 10-6 m2 cross section. Nichrome has a resistivity of 5.00 × 10-6 ?
(a) If the element dissipates 2040 W, what is its length?
(b) If 106 V is used to obtain the same dissipation rate, what should the length be?