The sun is the center of the solar system which is surrounded by the nine planets and they tend to orbit the sun in concentric circles with the sun as the center.
<h3>What is the solar system?</h3>
The term solar system has to do with the arrangement of the sun and the planets. The sun lies at the focus of the solar system. Now we know that there are nine planets that orbit around the sun. The distance between the planets and the sun depends on their relative proximity to each other.
Thus, the sun is the center of the solar system which is surrounded by the nine planets and they tend to orbit the sun in concentric circles with the sun as the center.
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1 and A
2 and B
3 and D
4 and C
<u>Answer :</u>
(a) d = 0.25 m
(b) d = 0.5 m
<u>Explanation :</u>
It is given that,
Frequency of sound waves, f = 686 Hz
Speed of sound wave at
is, v = 343 m/s
(1) Perfectly destructive interference occurs when the path difference is half integral multiple of wavelength i.e.
........(1)
Velocity of sound wave is given by :




Hence, when the speakers are in phase the smallest distance between the speakers for which the interference of the sound waves is perfectly destructive is 0.25 m.
(2) For constructive interference, the path difference is integral multiple of wavelengths i.e.
( n = integers )
Let n = 1
So, 


Hence, the smallest distance between the speakers for which the interference of the sound waves is maximum constructive is 0.5 m.
B. As job efficiency increases, stress levels decline (THIS IS WRONG)I think its between A. As job efficiency decreases, stress levels increaseD. As stress levels increase, job efficiency increases