A 9.00-cm-long wire is pulled along a U-shaped conducting rail in a perpendicular magnetic field. The total resistance of the wire and rail is 0.320 Ω. Pulling the wire at a steady speed of 4.00 m/s causes 4.30 W of power to be dissipated in the circuit.

0.45 N

Explanation:

Let Recall that,

The power formula is:

P = E²/R

Let A = the magnetic field

Let L = length of wire = 9.00cm = 0.09 m

let R = resistance of wire = 0.320 Ω

let v = velocity of the wire = 4 m/s

Let E = across the wire voltage

Let P = the power of the wire = 4.3 W

To Solve for E:

The formula of E = √PR

The Voltage from a magnetic field is given as,

E = vAL

We therefore Use E = E

√PR = vAL

to solve for A,

A = √PR/vL

BA = √4.3 (0.32) / (4) (.09) - = 0.173

A = 0.173 wA/m²

Let F be the pulling force

Let I be the current in the wire

P = I²R

I = √P/R

F = IAL

F = √P/RAL

F = √4.3/.32 (0.173) (.09)

F = 0.45N