Answer: C. good reflector of heat
Explanation:
In space, sunlight transfers heat by radiation to objects and bodies and this includes satellites and astronauts. In addition, although the peak of the sun's emission is in the visible region of the electromagnetic spectrum, a part is also emitted in infrared (transferring thermal energy or heat) and ultraviolet (especially in the upper part of the Earth's atmosphere).
That is why in space missions, objects and many satellites are covered by thin layers or sheets that reflect this thermal energy and thus avoid damaging the equipment due to high temperatures.
In this sense, among the reflective materials used are aluminum, silver, copper and gold; the latter being the most used because it does not corrode or oxidize (unlike silver and copper) and is more malleable than aluminum.
On the other hand, <u>astronauts are also vulnerable to the effects of infrared radiation, especially their eyes</u>, since the human eye has no receptors in the infrared spectrum. <u>That is why the astronaut's helmet visor is covered with a thin layer of gold to avoid the dangerous effects of solar radiation.</u>
Answer:
C. is correct option.
Explanation:
Speed of sound in a particular temperature depends upon bulk modulus and density of material.
It is directly proportional to bulk modulus of material and inversely proportional to the density.
As we move from air to aluminium, their density increase which decrease speed of sound in them. But as we move down to their bulk modulus also increases and increase in that bulk modulus is too much comparable to their increase in density.(You can google their density and bulk modulus respectively).
So, at the end their bulk modulus factor overcome the sound that decreased due to density.
And overall sound increases .
Therefore the speed of sound is higher in solids than in liquids.
I think it is "A'' 'It moves along straight lines in air and changes direction when it enters water.
Answer:
Explanation:
Given
Required
Determine the impulse
The impulse is calculated as follows:
Substitute values for Force and Time
<em>Hence, the impulse experienced is 8.0Ns</em>