The ozone layer traps heat from the sun's heat. only three-fourths are reflected back out into space by the ozone layer. the greenhouse effect traps carbon dioxide and so does the ozone layer.
Answer:
increasing the temperature of the rod
Explanation:
Sound wave is a longitudinal wave and its speed in a solid rod is given by the formula

here we know that
Y = young's modulus
= density of the medium
so as we increase the temperature of rod the density of the rod will decrease while the elasticity will remain same
So on increasing the temperature we can say that speed will increase due to decrease in the density
Answer:

Explanation:
The water droplet is initially neutral, it will obtain a 40 nC of charge when a charge of -40 nC is removed from the water droplet.
The charge on one electron, 
Let the N number of electrons have charge -40 nC, such that,
Now, mass of one electron = 
Therefore, mass of N electrons = 
It is the mass of the of the water droplet that must be removed in order to obtain a charge of 40 nC.
Let it is m times the total mass of the droplet which is 
Then,

It is the required fraction of mass of the droplet.