A long straight wire carrying current I₁ is placed in the plane of a ribbon carrying current I₂ parallel to the wire. The width of ribbon is b. The straight conductor is placed at a distance a from the nearer edge of ribbon. Find the force of attraction per unit length between the two.

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

$\frac{μ_{0} I_{1} I_{2}}{2 π} \log \frac{a + b}{a}$

$\frac{μ_{0} I_{1} I_{2}}{2 π} \log \frac{a}{a + b}$

$\frac{μ_{0} I_{1} I_{2}}{2 π} \log \frac{a}{b}$

$\frac{μ_{0} I_{1} I_{2}}{2 π} \log \frac{(a + b)}{a}$

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Consider an elementary strip of width dx on the sheet at a distance x from the wire.

Force on this element is, $dF = \frac{μ_{0} I_{1}}{2 πx} I_{2} dx$

Total force on unit length of sheet is

$\begin{array}{l} F = \int_{a}^{a + b} \frac{μ_{0} I_{1}}{2 πx} I_{2} dx \\ F = \frac{μ_{0} I_{1} I_{2}}{2 π} \int_{a}^{a + b} \frac{1}{x} dx = \frac{μ_{0} I_{1} I_{2}}{2 π} \log \frac{(a + b)}{b} \end{array}$

Watch 3-min video & get full concept clarity

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th

🔥 Start Your JEE/NEET Prep at Just ₹1999 / month - Limited Offer! Check Now!

Get Expert Academic Guidance – Connect with a Counselor Today!