A straight wire of mass 100 g and length 1.5 m carries a current of 2 A. It is suspended in mid air by a uniform horizontal magnetic filed as shown in the figure. What is the magnitude of the magnetic field? (acceleration due to gravity = $10 ms^{-2}$.)
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0.33 T
Mass of wire, $m=0.1kg$
$g=10m/s^2$ [Acceleration due to gravity]
$F_{gravity}=0.1×10=1N$
$F_{magnetic}=ILB\sin θ$
where,
$I=2A$
$L=1.5m$
B = magnetic field strength
$θ=90°$
$∴ F_{magnetic}=F_{gravity}$
$ILB=mg$
$2×1.5×B=1$
$B=\frac{1}{2×1.5}=\frac{1}{3}T$