A lightbulb contains Ar gas at a temperature of 295K and at a pressure of 75kPa. The light bulb is switched on, and after 30 minutes its temperature is 418 K. What is a numerical setup for calculating the pressure of the gas inside the light bulb at 418K?

Question

Assume the volume of the light bulb remains constant.

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Answer 1 · 2017-05-09T06:27:58

The assumption is quite reasonable.........

#P_1/T_1=P_2/T_2# given constant #n#, and constant #V#, conditions that certainly obtain with a fixed volume light bulb.

And so #P_2=P_1/T_1xxT_2#

#=(75*kPa)/(295*cancelK)xx418*cancelK#

#~=100*kPa#.

Had the light bulb been sealed at normal pressure during its manufacture, what do you think might occur when it is operated?