Consider two current carrying circular loops.Both are madefrom one strand of wire and both carry the samecurrent,but one has twice the radius of theother.Compared to the magnetic field at the center of the smallerloop ,the magnetic field at the center of the larger loopis a. 8 times stronger b. 4 times stronger c. 2 times stronger d. none of theabove Consider two current carrying circular loops.Both are madefrom one strand of wire and both carry the samecurrent,but one has twice the radius of theother.Compared to the magnetic field at the center of the smallerloop ,the magnetic field at the center of the larger loopis a. 8 times stronger b. 4 times stronger c. 2 times stronger d. none of theabove
Explanation / Answer
Let r be the radius ofthe smaller loop. The magnitude of magnetic fieldat the center of the loop is Bsmall =oI / 2r Where I is the current flowingthrough the loop But form given data the radiusof the larger loop is 2r Then the magnitude ofmagnetic field at the center of the loop is Blarge =oI / 2(2r) Blarge = oI / 4r The ratio of magnetic field at center of samller loopto larger loop is Bsmall / Blarge = 2 So the magnetic field at the center of thesmaller loop ,the magnetic field at the center of the larger loopis 2 times storanger. So correct option is C