Answer:
0.3 %
Explanation:
Earth cleans and replenishes the water supply through the hydrologic cycle. The earth has an abundance of water, but unfortunately, only a small percentage, is even usable by people.
Answer:
False
Explanation:
As we know that, the Balmer series gives the n values as,
.
.
Now the value of wavelength can be calculated as,
.
Here,
.
And
.
Now,
.
Therefore,

Therefore, the wavelength of Balmer series lies in visible region which is 547 nm.
Answer:

Explanation:
The energy of a photon is given by:

where
h is the Planck constant
c is the speed of light
is the wavelength of the photon
In this problem, we have a microwave photon with wavelength

Substituting into the equation, we find its energy:

Answer:
2 m/s
Explanation:
The first part of the question the car is going in reverse or negative along the x axis. Then the second part the car is moving forward along the x axis. So the car would only have velocity in the current direction of movement. So our equation for velocity is as follows.
v = d/t
v = 10 m/5 s
v = 2 m/s
Our values can be defined like this,



The problem can be solved for part A, through the Work Theorem that says the following,

Where
KE = Kinetic energy,
Given things like that and replacing we have that the work is given by
W = Fd
and kinetic energy by

So,

Clearing F,

Replacing the values


B) The work done by the wall is zero since there was no displacement of the wall, that is d = 0.