Question

Please solve this question with
explanation

Answer 1

magnetic field due to coil is mew/2. I/r,so here mew /2 and mew /2 get cancelled due to finding of ratios and I's also get cancelled because they connected in series i.e., same current passes through those both and we remain with 1/10/1/40=40/10=4:1.....

so,option B ,which is 4:1 is the correct answer..........