Saved Bookmarks
| 1. |
Two circular coils made of same material having radii 20cm & 30cm have turns 1 00 & 50 respectively. If they are connected a) in series b) in parallel c) separately across a source of emf find the ratio of magnetic inductions at the centres of circles in each case |
|
Answer» SOLUTION :a) `B=(mu_(0)ni)/(2r)` COILS are in series `rArr` I is same both `Bpropn/r` `(B_(1))/(B_(2))=100/50xx30/20=3:1` b) coils are parallel `rArr` potential difference is same `iprop1/R` where `R=(p(n2pir))/A` where A is area of cross SECTION of wire which is same for both `rArrRpropnr,iprop1/(NR)` but `B_(0)=(mu_(0)ni)/(2r)` `rArrBpropn/rxx1/(nr)rArrBprop1/(r^(2))therefore(B_(1))/(B_(2))=(30/20)^(2)=9/4` C) For the coils, potential difference is same `iprop1/R` where `R=(p(n2pir))/A,Rpropnr` `Iprop1/(nr)rArrB_(0)1/(r^(2))therefore(B_(1))/(B_(2))=9/4` |
|