Question
A conducting wire is stretched by applying a deforming force, so that its diameter decreases to 40 \% of original value. The percentage change in its resistance will be
BITSAT
Physics
Current Electricity
2024
BITSAT 2024 (Memory Based Paper 3)
BITSAT Physics Question (2024) — Solution
Options
- A. 0.9 \%
- B. 0.12 \%
- C. 1.6 \%
- D. 0.5 \%
Answer
C. 1.6 \%
Step-by-step solution
On stretching, volume of wire remains constant. So, V=A l or l= V A array ll & R= l A = V A^2 = V ^2 D^4 16 = 16 V ^2 D^4 \\ & R R =-4 D D =-4(-0.4)=1.6 \% array
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