問題詳情

50. A mall bulb is rated at 7.50 W when operated at 125 V. Thetungsten filament has a temperature coefficient of resistivity a = 4.50 x 10-3/ ℃. Wher is hot and glowing, its temperature is seven times room temperature (20 ℃). What is the resistance of the filament (in ohms) at room temperature?
(A) 240
(B)1350
(C) 2080
(D) 4530
(E) 5630

參考答案

答案：B

統計：A:0,B:0,C:0,D:1,E:0

難度：計算中