Question

A horse shoe magnet is placed on a mass balance such that a uniform magnetic field of magnitude B runs between it from North to South. A coil of resistance R is connected to a battery which supplies a potential difference of V across the coil and is suspended such that a section of the coil of length L meters lies between it with current running from East to West. The mass balance measures a mass of M. • What is the measured change in mass due to the effect of Fmag? • What is the total measured mass of the magnets? Keep in mind the effect of Newton's third law.

Answer 1

(a) Measured change in mass (Δm) = BVL/Rg

(b) Total measured mass M' = M - BVL/Rg

Step-by-step explanation:

Current (I) across is coil is given by the formula;

I = V/R ------------------------1

The magnetic force is given by the formula;

Fb = B*I*L -------------------2

Putting equation 1 into equation 2, we have;

Fb = B*V*L/R -------------------3

Change in mass (Δm) is given as:

Δm = Fb/g -----------------------4

Putting equation 3 into equation 4, we have;

Δm = BVL/Rg

Therefore, change in mass (Δm) = BVL/Rg

2. Since B runs from North to South and current running from East to West, then the magnetic force is directed upward.

Therefore,

Total measure mass M' = M - BVL/Rg