JEE Mains · Physics · STD 12 - Current electricity
- JEE Mains 2023
- Medium
- Numerical
A uniform metallic wire carries a current \(2\,A\). when \(3.4\,V\) battery is connected across it. The mass of uniform metallic wire is \(8.92 \times 10^{-3} \,kg\). density is \(8.92 \times 10^3\,kg / m ^3\) and resistivity is \(1.7 \times 10^{-8} \Omega- m\). The length of wire is \(l=............\,m\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(10\)
Step-by-step Solution
Detailed explanation
\(I =2\,A\)
\(\Delta V =3.4\,V\)
Using Ohm's Law
\(R =\frac{3.4}{2}=1.7 \Omega\)
\(1.7=\frac{\rho L }{ A }\)
\(L =\frac{1.7( A )}{\rho}\)
\(M =(\text { density volume })\)
\(Volume =\frac{8.92 \times 10^{-3}}{8.92 \times 10^3}=10^{-6}\)
\(L ^2=\frac{1.7}{\rho}\left(10^{-6}\right)=\frac{1.7}{1.7} \times 10^2\)
\(L =10\,m\)
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