Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Medical
  • What length of wire (Specific resistance is n

What length of wire (Specific resistance 48\times10^{-8}\mathrm{\Omega m} is needed to make a resistance of \mathrm{4.2\Omega } ? \mathrm{(Diameter =0.4mm) }

Option: 1

\mathrm{3.1m}


Option: 2

\mathrm{4.1m}


Option: 3

\mathrm{2.1m}


Option: 4

\mathrm{1.1m}


Answers (1)

best_answer

Given, \rho=48 \times 10^{-8} \Omega \mathrm{m}

\mathrm{ R=4.2 \Omega }

\mathrm{ D=0.4 \mathrm{~mm}}

use,\mathrm{R=\rho \frac{l}{A} }

\mathrm{ l=\frac{R A}{\rho}=\frac{4.2 \times 22 \times\left(0.2 \times 10^{-3}\right)^2}{7 \times 48 \times 10^{-8}} }

\mathrm{ =\frac{0.6 \times 22 \times 0.04 \times 10^{-6}}{48 \times 10^{-8}} }

\mathrm{ l=\frac{13.2 \times 0.04 \times 10^2}{48} }

\mathrm{ l=1.1 \mathrm{~m} }

Hence option 4 is correct.






 

Posted by

Sanket Gandhi

View full answer

NEET 2024 Most scoring concepts

    Just Study 32% of the NEET syllabus and Score up to 100% marks

Similar Questions

Trending Articles/News

anam-khan

NEET UG 2026 Registration LIVE: NTA to begin NEET form soon at neet.nta.nic.in; exam date, fees updates
anam-khan

NEET UG 2026 LIVE: NTA NEET registration soon at neet.nta.nic.in; exam date, how to apply, latest updates
anam-khan

50 MBBS students from Vaishno Devi medical college reallocated to govt colleges after NMC action

Latest Question