the whole of a sealed empty dusty room is kept at a constant temperature of 15c light shines into the room through a small outside window an observer points a tv camera with a magnifying lens into the room through a second small window set in an inside wall at right angles to the outside wall dust particles in the room show up on the tv monitor screen as tiny specks of light (a) in the space below draw a diagram to show the motion of one of the specks of light over a short period of time