Engineering Board Exam Reviewer · Voltage, Current and Resistance · hard
A copper wire has a resistance of R at 20° C. At what temperature will its resistance be doubled? (Use =0.00393/° C at 20° C.)
- 147.2° C
- 254.5° C
- 274.5° C
- 40° C
Answer
C. 274.5° C
Solution
R2=R1[1+ (T2-T1)]=2R1 (T2-T1)=1 T2-20=1/0.00393=254.5. So T2 274.5° C.
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