Answer:
To increase the conductivity of the material.
Explanation:
Generally , the group 4 elements are non conductor but in certain conditions, such as doping or the increase in temperature, they becomes conductor.
The doping is the process of mixing of pentavalent or the trivalent material into tetra valent material in the very small amount, so that the material becomes conductor.
In making a diode we need two types of the materials, n type semiconductor and p type semi conductor.
When the trivalent impurity is added in the tetra valent element, the semiconductor becomes n type because an electron is left for the conduction.
When the pentavalent impurity is added in the tetra valent element, the semiconductor becomes p type because a hole is left for the conduction.
Mario Molina helped to bring about the 1987 Montreal Protocol on substances that result in depletion of the Ozone Layer.
<h3>What is ozone layer?</h3>
The topmost layer of the atmosphere which protect the harmful UV rays from the Sun to reach the Earth surface.
Mario Molina has the great contribution in science field. He tried hard and succeeded in passing an international agreement to eliminate CFCs also called as Chloro Fluoro Carbons and other ozone-depleting chemicals.
These CFCs were used in jet planes which depleted the ozone layer and a hole was observed over Antarctica.
Learn more about ozone layer.
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Answer:
Explanation:
The peak wavelength of the spectral distribution can be found by using Wien's displacement law:
where
is Wien's displacement constant
T is the absolute temperature
For the cosmic background radiation, the temperature is
T = 2.7 K
So, the corresponding peak wavelength is
Answer:
t=240s
Explanation:
Distance=120m
Acceleration=-5m/s^2
v=0
Let u=x m/s
Using equation v^2-u^2=2as:-
0-x=2(-5)(120)
-x=-1200
x=1200m/s
Using now equation v=u+at:-
0=1200+-5t
5t=1200
t=240s
Answer:
proton proton proton proton
