일반물리학 2 — Current and Resistance: Problem 15

15 A heater contains a Nichrome wire (resistivity \(5.0 \times 10^{-7} \Omega \cdot \text{m}\)) of length 5.85 m, with an end-to-end potential difference of 112 V, and with a dissipation power of 4000 W. (a) What is the wire’s cross-sectional area? (b) If 100 V is used to obtain the same dissipation rate, what should the length be?