Answer:
Total 3 holes are available for conduction of current at 300K.
Explanation:
In order to develop a semiconductor, two type of impurities can be added as given below:
- N-type Impurities: Pentavalent impurities e.g. Phosphorous, Arsenic are added to have an additional electron in the structure. Thus a pentavalent impurity creates 1 additional electron.
- P-type Impurities: Trivalent impurities e.g. Boron, Aluminium are added to have a positive "hole" in the structure. Thus a trivalent impurity creates 1 hole.
Now for estimation of extra electrons in the impured structure is as

Now for estimation of "holes" in the impured structure is as

Now when the free electrons and "holes" are available in the structure ,the "holes" will be filled by the free electrons therefore

So total 3 "holes" are available for conduction of current at 300K.
28 times stronger than the force of gravity on the surface of the Earth.
I think it’s cause no change i think
If you think about it, irregular galaxies dont really have a describable shape, as you can tell by the name. So B.
Answer:

Explanation:
We know that the gravity on the surface of the moon is,
<u>Gravity at a height h above the surface of the moon will be given as:</u>
..........................(1)
where:
G = universal gravitational constant
m = mass of the moon
r = radius of moon
We have:
is the distance between the surface of the earth and the moon.
Now put the respective values in eq. (1)

is the gravity on the moon the earth-surface.