What is the temperature of the argon in the electric bulb that creates this new steady pressure? An electric light bulb has a volume of 200 cm^3. It contains argon gas at a pressure of 1.1x10^5 pa and a temperature of 25 deg C. When the light is switched on, the pressure increases to a steady 1.8x10^5 pa.

Expert Answers

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Here we use the ideal gas law. The volume of the bulb is a constant 200 cm^3. Initially the pressure is 1.1*10^5 pa when the temperature is 25 deg C.

When the bulb is switched on, there is a change in the temperature of the gas. The pressure also changes to 1.8*10^5 pa.

Now the ideal gas law gives P*V= n*R*T

Here V, R and n are constants.

The pressure is proportional to the temperature.

P1 = K*T1

=> 1.1*10^5 = K*(25 + 273)

P2 = K*T2

=> 1.8*10^5 = K*T2

T2 + 273 / 298 = 1.8*10^5 / 1.1*10^5

=> T2 + 273 = 487.63

=> T2 = 214.63

Therefore the new temperature in the bulb is 214.63 degree C.

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