a cabel consists of 10 strands of copper wire each of cross-section area 1.1x10^-3 cm^2. Calculate (a) the resistance per meter of the cable (b) the minimum number of strands which would be required if the resistance per meter is not to exceed 0.010ohms. (resistivity of copper = 1.8 x 10^-8 ohm meter.)

resistance=Length*resisitivity*numberWires/Area

for resitance per meter..
resistance/meter=reisiitivity*numberwires/Area
You are given resisitivty, numberwires, Area is given (convert to square meter , ie 1.1e-3cm^2*1e-4 or 1.1e-7 m^2

Go solve.

To calculate the resistance per meter of the cable, we can use the formula:

Resistance (R) = (Resistivity * Length) / Cross-sectional area

Given:
Number of strands (n) = 10
Cross-sectional area (A) = 1.1 x 10^-3 cm^2 = 1.1 x 10^-7 m^2
Resistivity of copper (ρ) = 1.8 x 10^-8 ohm meter

(a) Resistance per meter of the cable (R):

R = (ρ * Length) / A

To find R, we need the length of the cable. If the length is provided, we can substitute it into the formula.

(b) To calculate the minimum number of strands required, we need to rearrange the formula to solve for n:

n = (ρ * Length) / (A * R)

Given:
Resistance per meter (R) = 0.010 ohms

We now need to calculate the length of the cable. If the length is provided, we can substitute it into the formula to find the minimum number of strands required.

To calculate the resistance per meter of the cable, we need to use the formula for resistance:

Resistance (R) = (Resistivity x Length) / Cross-section area

Given:
Number of strands (n) = 10
Cross-section area of each strand (A) = 1.1 x 10^-3 cm^2
Resistivity of copper (ρ) = 1.8 x 10^-8 ohm meter

(a) To calculate the resistance per meter (R):

First, convert the cross-section area from cm^2 to m^2:
A = (1.1 x 10^-3 cm^2) x (1 m^2 / 10000 cm^2)
A = 1.1 x 10^-7 m^2

Then, use the formula to find the resistance per meter:
R = (ρ x Length) / A

Since the length is not provided, we won't be able to calculate the exact resistance per meter without that information.

(b) To determine the minimum number of strands required to keep the resistance per meter below 0.010 ohms:

We can rearrange the resistance formula to solve for the length:
Length = (Resistance x Cross-section area) / Resistivity

Since the resistance per meter should not exceed 0.010 ohms, we can use this value for resistance and rearrange the formula to solve for the length:

Length = (0.010 ohms x 1.1 x 10^-7 m^2) / (1.8 x 10^-8 ohm meter)

Length ≈ 6.11 meters

Now we can substitute this length back into the resistance formula to find the actual resistance:

R = (1.8 x 10^-8 ohm meter x 6.11 meters) / 1.1 x 10^-7 m^2

R ≈ 1 x 10^-8 ohms

Since the resistance per meter is the same for each strand, the number of strands (n) needed to keep the resistance below 0.010 ohms will be:

n = (0.010 ohms per meter) / (1 x 10^-8 ohms)

n ≈ 1000 strands

Therefore, the minimum number of strands required is 1000.