Answer:
1. Burning coal contributes to sulfur aerosols in the stratosphere; these sulfur aerosols have moderated global warming.
Explanation:
Sulfur aerosols both absorb as well as scatter solar radiation coming from the sun , thus saving the earth from getting wormed up . In this way it has moderating effect on the global warming . This is also called global dimming effect. Less of the solar radiation is able to reach earth surface due to these aerosol.
Answer: Rods
Explanation:
The rod cells in the retina are the reason we are able to see at night and in dim light. They exist on the edges of the retina which is why they are also very useful for the peripheral vision of a human.
Rod cells number over 90 million in the eyes and although very useful for seeing in dimmer light, they are not very useful for color vision which is why humans see less colors in the dark.
Answer:
Option D
The frequency
Explanation:
The speed of wave is depedant only on the wavelength and frequency of waves since it is given by s=fw where s is the speed, f is frequency and w is the wavelength. Since the options given has only one factor, that is frequency, hence option D is correct. In case we had wavelength could be among the options, both would be correct.
Answer:
the magnitude of the work done by the two blocks is the same.
Explanation:
The work done by block a on block b is given by:

where Fa is the force exerted by block a on block b, and d is the distance they cover.
The work done by block b on block a is given by:

where Fb is the force exerted by block b on block a, and d is still the distance they cover.
For Newton's third law, the force exerted by block a on block b is equal to the force exerted by block b on block a, therefore

and so

Answer:
Steel is almost 2.9 times heavier the aluminium.