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Resistance Thermometers

Let i0 be the...

Question

Let i₀ be the thermionic current from a metal surface when the absolute temperature of the surface is T₀. The temperature is slowly increased and the thermionic current is measured as a function of temperature. Which of the following plots may represent the variation in (i/i₀) against (T/T₀)?

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Solution

(d)

Since the thermionic current is directly proportional to the square of the temperature of the surface emitting thermions, the graph is parabolic.

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