Magnetic Effects Of Current Question 16
Question 16 - 30 January - Shift 2
A current carrying rectangular loop PQRS is made of uniform wire. The length $PR=QS=5 cm$ and $PQ=RS=100 cm$. If ammeter current reading changes from I to 2I, the ratio of magnetic forces per unit length on the wire PQ due to wire RS in the two cases respectively $f_PQ^{I}: f_PQ^{2 I}$ is :
(1) $1: 2$
(2) $1: 4$
(3) $1: 5$
(4) $1: 3$
Show Answer
Answer: (2)
Solution:
Formula: Magnetic field due to a straight wire
$F \propto I_1 I_2$
$F_I: F _{2 I}=1: 4$
