A straight wire of mass 300 g and length 2.5 m carries a current of 3.5 A . It is suspended in mid-air by a uniform horizontal magnetic field B. What is the magnitude of the magnetic field?

Question

A straight wire of mass 300 g and length 2.5 m carries a current of 3.5 A . It is suspended in mid-air by a uniform horizontal magnetic field B. What is the magnitude of the magnetic field? (A)  0.654 T  (B)  0.336 T  (C)  1.576 T  (D)  0.939 T

Tardigrade Admin · Accepted Answer

Here weight of the wire is balanced by the extene magnetic force. So, Bil=mg B=(mg/il) =(300× 10-3× 10/35× 2.5)=0.34 T

Q. A straight wire of mass $300 g$ and length $2.5 m$ carries a current of $3.5 A$ . It is suspended in mid-air by a uniform horizontal magnetic field $B$ . What is the magnitude of the magnetic field?

$0.654 T$

$0.336 T$

$1.576 T$

$0.939 T$

Here weight of the wire is balanced by the extene magnetic force.
So, $B i l = m g$
$B = \frac{m g}{i l}$
$= \frac{300 \times 10 ^{- 3} \times 10}{35 \times 2.5} = 0.34 T$

Q. A straight wire of mass 300g and length 2.5m carries a current of 3.5A . It is suspended in mid-air by a uniform horizontal magnetic field B. What is the magnitude of the magnetic field?

0.654T

0.336T

1.576T

0.939T