Answer:
Explanation:
Given
No of atoms of hydrogen 
Temperature of room 
Thermal energy of the atoms is given by

where k=boltzmann constant


Hence the energy of the atoms is 
Answer:
The flea will reach to a height of 5.2 cm.
Explanation:
Let us assume it is given that, a flea reaches a takeoff speed of 1.0 m/s over a distance of 0.50 mm.
Initial speed, u = 1 m/s
Initial distance, x = 0.5 mm
We need to find the height reached by the flea. Using third equation of motion to find it.
At maximum height, its final speed, v = 0

Here, a = -g

or
h = 5.2 cm
So, the flea will reach to a height of 5.2 cm.
Answer with Explanation:
The direction of the electric field line at any point gives us the direction of the electric force that will act on a positive charge if placed at the point. We know that if we place a charge in an electric field it will experience a force, as we know that force is a vector quantity hence it requires both magnitude and direction for it's complete description. The direction of this electric force that acts on a charge is given by the direction of the electric field in the space. In case the charge is negatively charged electric force will act on it in the direction opposite to the direction of electric field at the point.