Question

Give reason for the following:
a
The metal knob feels colder than the wooden knob at the same temperature.
b The appearance of fuel tank is usually shiny and smooth.
c) A hot air balloon rises up in the sky.
d) The water pipe in a solar water heater is bent into the shape as
given in the picture.​

Answer 1

Answer:

Hot air balloons fly when the air inside the hot air balloon is less dense than the air surrounding it. Hot air is less dense than cool air; the heated air causes the balloon to rise simply because it is lighter than an equal volume of cold air. ... A hot air balloon uses a burner to heat up the air inside the balloon