A copper wire of length 10 cm is in a magnetic field of 0.30 T.If it has a mass of 20 g,what minimum current through the wire would cause a magnetic force equal to its weight?
A) 4.9 A
B) 6.5 A
C) 2.0 A
D) 1.3 A

Question

Quizplus · Accepted Answer

The weight of the wire can be calculated using the formula:

W = mg

where W is the weight, m is the mass, and g is the acceleration due to gravity (9.8 m/s^2).

W = (20 g) x (9.8 m/s^2) = 0.196 N

The magnetic force on the wire can be calculated using the formula:

F = BIL

where F is the force, B is the magnetic field, I is the current, and L is the length of the wire.

To find the minimum current that would cause a magnetic force equal to the weight of the wire, we can set the two equations equal to each other and solve for I:

F = BIL = mg

I = mg / BL

Substituting the given values:

I = (0.02 kg x 9.8 m/s^2) / (0.1 m x 0.3 T) = 6.5 A

Therefore, the answer is B) 6.5 A.

A Copper Wire of Length 10 Cm Is in a Magnetic