A copper wire of length 11 cm is in a magnetic field of 0.42 T.If it has a mass of 19 g,what is the minimum current through the wire that would cause a magnetic force equal to its weight?

Question

Quizplus · Accepted Answer

The magnetic force on a current-carrying wire in a magnetic field is given by:
 Fm = BIL 
where Fm is the magnetic force, B is the magnetic field strength, I is the current, and L is the length of the wire.
The weight of the wire can be calculated as:
 W = mg 
where W is the weight, m is the mass, and g is the acceleration due to gravity, which is approximately 9.81 m/s^2.
For the magnetic force to be equal to the weight, we need:
 Fm = W 
Therefore, we can set these two equations equal to each other and solve for the current:
 BIL = mg 
 I = mg/BL 
Substituting the given values, we get:
 I = (0.019 kg)(9.81 m/s^2)/(0.11 m)(0.42 T) = 3.97 A
Therefore, the minimum current required to create a magnetic force equal to the weight of the wire is approximately 4.0 A, which corresponds to choice C.

A Copper Wire of Length 11 Cm Is in a Magnetic