Question
The resistance of a wire is 5 . It's new resistance in ohm if stretched to 5 times of its original length will be :
BITSAT
Physics
Current Electricity
2023
BITSAT 2023 (Memory Based Paper 1)
BITSAT Physics Question (2023) — Solution
Options
- A. 625
- B. 5
- C. 125
- D. 25
Answer
C. 125
Step-by-step solution
Let resistance of a wire R and length 1 . R = A =5 Volume of wire is constant in stretching V_i=V_f A_i _i=A_f _f A = A ^ (5 ) A ^ = A 5 R_f= _f A_f = (5 ) ( A 5 ) =25 ( A )=25 5=125
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