Resistance and temp co-efficient?

  • Thread starter neduet
  • Start date
  • Tags
    Resistance
In summary, the resistance of a conductor with a cross-section of 10 cm2 and specific resistance of 7.5 ohm cm at 0 degree C will be 90,000 ohm per kilometer when the temperature is 40 degree C, assuming a temperature coefficient of 0.005 / degree C.
  • #1
neduet
64
0

Homework Statement



A conductor has cross-section of 10 cm2 and specific resistance of 7.5 ohm cm at 0 degree C
what will be its resistance in ohm per/kilometer when the temperature is 40 degree C ?
take temperature co-efficient of the material is 0.005 / degree C

i can't find the solution of it. please give me solution if you can
please help me

Homework Equations


Resistance of a wire in Ω
R = ρL/A
ρ is resistivity of the material in Ω-cm
L is length in cm
A is cross-sectional area in cm²

The Attempt at a Solution

R = (7.5 Ω-cm)(L) / 10 cm²
R/L = 0.75 Ω/cmR/L = 0.75 Ω/cm x 100000 cm/km = 75000 Ω/km
R/L = 75000 Ω/km x [1+ (0.005/C)*40C]
R/L = 90000 Ω/km
 
Physics news on Phys.org
  • #2

Therefore, the resistance of the conductor at 40°C would be 90,000 Ω/km. This calculation takes into account the temperature coefficient of the material, which indicates how much the resistance changes with temperature. In this case, the resistance increases by 0.5% per degree Celsius. So at 40°C, the resistance would be 9,000 Ω higher than at 0°C.
 

1. What is resistance?

Resistance is the measure of opposition to the flow of electric current. It is measured in ohms (Ω) and is dependent on the material, length, and cross-sectional area of a conductor.

2. How does temperature affect resistance?

As temperature increases, the resistance of a material also increases. This is because as temperature increases, the atoms in the material vibrate more, causing more collisions and hindering the flow of electrons.

3. What is the temperature coefficient of resistance?

The temperature coefficient of resistance (TCR) is a measure of how much the resistance of a material changes per degree of temperature change. It is usually represented by the symbol α and is measured in units of ohms per degree Celsius (Ω/°C) or ohms per degree Kelvin (Ω/K).

4. How is the temperature coefficient of resistance calculated?

The temperature coefficient of resistance can be calculated by taking the change in resistance (ΔR) divided by the original resistance (R) and the change in temperature (ΔT).

TCR (α) = (ΔR/R) / ΔT

5. Why is the temperature coefficient of resistance important?

The temperature coefficient of resistance is important because it helps to predict how a material's resistance will change with temperature. This is especially important in electronic devices where precise resistance values are necessary for proper functioning. TCR also helps to determine the operating temperature range for a material and can be used for temperature compensation in electronic circuits.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
741
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
4K
  • Introductory Physics Homework Help
Replies
10
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
2K
Replies
96
Views
9K
  • Introductory Physics Homework Help
Replies
7
Views
9K
  • Introductory Physics Homework Help
Replies
25
Views
2K
Back
Top