Question

Опір вольфрамової нитки лампи при 20°С дорівнює 20 Ом. Опір тієї самої лампи в робочому стані 188 Ом. Яка температура розжарення лампи? (температурний коефіцієнт опору для вольфраму а=0,005 К²)

Answer 1

Calculating the Temperature of the Lamp

To calculate the temperature of the lamp, we can use the formula for the temperature coefficient of resistance:

Rt = R0 * (1 + a * (t - t0))

Where: - Rt = resistance at temperature t - R0 = resistance at reference temperature t0 - a = temperature coefficient of resistance - t = temperature for which the resistance is to be found - t0 = reference temperature

Given: - Resistance at 20°C (reference temperature), R0 = 20Ω - Resistance in the working state, Rt = 188Ω - Temperature coefficient of resistance for tungsten, a = 0.005 K^-1 - Reference temperature, t0 = 20°C

We can rearrange the formula to solve for the temperature t:

t = ((Rt / R0) - 1) / a + t0

Substitute the given values: t = ((188 / 20) - 1) / 0.005 + 20

Calculating: t ≈ 2938°C

Conclusion

The temperature of the lamp when it is in a working state is approximately 2938°C.