Question

the answers are:

a. 0.24, current flows left to right

b. 0.24, current flows right to left

c. 0.41, current flows tight to left

d. 0.65, current flows left to right

e. 0.65, current flows right to left

A horizontal length of current-carrying wire is suspended from two identical flexible leads that are under tension due to the weight of the wire. The wire is oriented at right angles to a uniform magnetic field that has a magnitude of 3 T and is directed into the screen of the figure. The length L of the wire is 5 cm and its mass m is 10 g. What current will produce a magnetic force on the wire such that it doubles the tension in the flexible leads, and which way is the current flowing through the wire? Current-carrying wire suspended from identical flexible leads B® magnetic field (into the screen) Ceiling 1, current-carrying wire L

Answer 1

The force on the rod will be equal to the weight of the rod to make the tension twice of its magnitude.

Now, m.g = B.i.l

here, m= mass of the rod= 10g = 0.01 kg

g = gravitational acceleration= 9.8 m/s²

B = magnetic field= 3 T

i = current in the rod

l = length of the rod= 5 cm = 0.05 m

Now, 0.01×9.8 = 3×i ×0.05

=> i = 0.65 Amp (approx)

The current will flow from left to right.

The correct option is : d) 0.65, current flows left to right.