A piece of copper wire has a resistance per unit length of 6.50 10-3 /m. The wire is wound into a thin, flat coil of many turns that has a radius of 0.170 m. The ends of the wire are connected to a 12.0 V battery. Find the magnetic field strength at the center of the coil.

_________ T

B = (4pi x 10^-7)(12.0) / (6.5 x 10^-3)(4pi (0.170^2))

B = 0.000015082 / 0.002360899

B = 6.39 x 10^-3T

1. 👍
2. 👎
3. 👁
4. ℹ️
5. 🚩
1. B = mu H = (4 pi*10^-7)*i N/(2 r)
N is the number of turns.
i is the current
i = V/R
R = N* 2 pi r * (6.5*10^-3 ohm/m)
B = [(4 pi*10^-7)*V*N]/[(N*4*pi*r^2*(6.5*10^-3)]
= 10^-7 V/[r^2*(6.5*10^-3 ohm/m)]
The 4 pi factors and the number of turns N both cancel out. I agree with your formula and answer.

1. 👍
2. 👎
3. ℹ️
4. 🚩

## Similar Questions

1. ### probability

A factory produces copper wires. A blue mark is placed on a very long length of copper. The wire is then cut into pieces. The lengths of different pieces are independent, and the length of each piece is distributed according to

2. ### Math

Problem: What is the resistance of a 3.9-m length of copper wire 1.1 mm in diameter? The resistivity of copper is 1.68×10^−8Ω⋅m. Answer--> R=______Ω

3. ### physics

Consider two copper wires with the same cross-sectional area. Wire A is twice as long as wire B. How do the resistivities and resistances of the two wires compare? CHECK ALL THAT APPLY Wire A and wire B have the same resistance.

4. ### Physics

Two wires are identical, except that one is aluminum and one is copper. The aluminum wire has a resistance of 0.835. What is the resistance of the copper wire? Take the resistivity of copper to be 1.72 x 10-8 Ω·m, and that of

1. ### physics

A certain copper wire has a resistance of 12.0 \Omega.At what point along its length must the wire be cut so that the resistance of one piece is 5.0 times the resistance of the other?

2. ### Physics

Which statement correctly describes the resistivity of a wire?(1 point) A.) Resistivity depends on the current through the wire and has units of ohms. B.) Resistivity depends on the material the wire is made from and has units of

3. ### Physics

A piece of Nichrome wire has a radius of 8.0 10-4 m. It is used in a laboratory to make a heater that dissipates 2.00 102 W of power when connected to a voltage source of 120 V. Ignoring the effect of temperature on resistance,

4. ### physics

A potential difference of 12 V produces a current of 0.90 A in a piece of copper wire. What is the resistance of the wire?

1. ### physics

A copper wire has a resistance of 0.425 at 20.0°C, and an iron wire has a resistance of 0.455 at the same temperature. At what temperature are their resistances equal?

2. ### physics

A wire of initial length L0 and radius r0 has a measured resistance of 2.5 . The wire is drawn under tensile stress to a new uniform radius of r = 0.45r0. What is the new resistance of the wire?

3. ### Physics!! Help!!!!!

A wire of length L and cross-sectional area A has resistance R. What will be the resistance R_stretched of the wire if it is stretched to twice its original length? Assume that the density and resistivity of the material do not

4. ### physics

A copper wire has a resistance of 1.02 Ω at 20.0°C. What is its resistance at 60°C? The temperature coefficient of resistivity for copper is 0.0039 (C°)—1.