Answer:
The resistance of the tungsten coil at 80 degrees Celsius is 15.12 ohm
Explanation:
The given parameters are;
The resistance of the tungsten coil at 15 degrees Celsius = 12 ohm
The temperature coefficient of resistance of tungsten = 0.004/°C
The resistance of the tungsten coil at 80 degrees Celsius is found using the following relation;
R₂ = R₁·[1 + α·(t₂ - t₁)]
Where;
R₁ = The resistance at the initial temperature = 12 ohm
R₂ = The resistance of tungsten at the final temperature
t₁ = The initial temperature = 15 degrees Celsius
t₂ = The final temperature = 80 degrees Celsius
α = temperature coefficient of resistance of tungsten = 0.004/°C
Therefore, we have;
R₂ = 12×[1 + 0.004×(80 - 15)] = 15.12 ohm
The resistance of the tungsten coil at 80 degrees Celsius = 15.12 ohm.