The experiment was a box heated with a 40w light bulb for 20 minutes and then allowed to let cool for 20 minutes. There was two temperature sensors that measured the heat of the box and the heat outside of an insulation material.
Dimensions of Box: l=29.21cm w=27.94cm h=30.48cm
Volume: ?
Inside initial temperature: 76.6 degrees F
Inside maximum temperature: 115.1 degrees F
Inside final surface temperature: 96.5 degrees F
Top of insulation initial surface temperature: 76.2 degrees F
Top of insulation maximum surface temperature: 78.0 degrees F
Top of insulation final surface temperature: 78.0 degrees F
Heating time (seconds):1200 s
Cooling time (seconds):1200 s
Questions
1. Mass of air being heated
2. Energy gained by the air in the box during heating - in joules
3. Energy lost by the air in the box during cooling - in joules
4. Net energy retained within the box - in joules
I CAN NOT FIND OUT HOW TO DO THIS PLEASE HELP!!!!!!
Update:Closed Box
Answers & Comments
Verified answer
pls specify whether it is a open box or closed box.
if it is a open box mass doesn't remain constant as the gas expands and escapes during heating.
if it is a closed box mass=volume x density ; density of air at atmospheric pressure may be approx. 1.2 kg/ m 3
energy gained or lost is a s you said Q = M Cp Delta T Cp of air is 1.005 kJ/kg K