Question

A wire long and with mass is positioned horizontally near the earth's surface and perpendicular to a horizontal magnetic field of magnitude . What current I must flow through the wire in order that the wire accelerate neither upwards nor downwards

Answer 1

The question is incomplete. The complete question is :

A wire 0.6 m long and with mass m = 11 g is positioned horizontally near the earth's surface and perpendicular to a horizontal magnetic field of magnitude B = 0.4 T. What current I must flow through the wire in order that the wire accelerate neither upwards nor downwards? The magnetic field is directed into the page.

Solution :

Given :

Length of the wire, L = 0.6 m

Mass of the wire length, m = 11 g

                                             = $11 \times 10^{-3}$ kg

Magnetic field , B = 0.4 T

Know we know that :

ILB = mg

or $I=\frac{mg}{BL}$

 $I= \frac{(11 \times 10^{-3})(9.81)}{(0.4)(0.6)}$

 $I=0.44963\ A$

 $I = 449.63 \ mA$