Phy...........

Question

Joe has closed all the windows of his car and parked his car under the Sun for three hours .
a ) When he opens a car door , he fells that the car inside is very hot . Explain briely why the car inside gets hot .
b ) Some drivers use a shiny shield to reduce the temperature rise in their cars . Explain briefly how it works .

Answer 1

a) This is similar to effect of a green house. The visible light and short wavelength infrared radiation from the sun pass through the glass of the car and are absorbed by the object inside the car, but the long wavelength infrared radiation which is re-radiation from the heated objects inside the car is unable to pass through the glass of the car. The trapping of the long wavelength infrared radiation leads to more heating and a higher resultant temperature inside the car.
b) The radiations from the sun pass through the glass of the car, and most of the radiations are immediately reflected by the shiny shield. The reflected radiations leave the car through the glass, and cause much less heating effect than the case without a shiny shield.