Answer:
option (c)
Explanation:
According to the doppler's effect, the frequency of sound decreases.
If there is a relative motion between the source and the observer, the frequency of sound changes apparently.
the formula of the doppler effect is given by
where, f is the real frequency, v be the speed of sound, vo be the speed of the observer, here, the bus is the observer.
So, the value of f' < f
Within the system of the same star, the period of a planet's orbit is
proportional to the 3/2 power of its distance from the central body.
(Kepler's empirical third law of planetary motion, promoted to being
etched in stone by Newton's gravitation.)
(4) ^ 3/2 = <em>8 times</em> as long.
Answer:
D, rubber
Explanation:
Metals have free electrons, and are very bad as insultators. Metals conduct electricity very well. On the other hand, rubber has no free electrons and does not conduct electricity very well
Answer: Option (C) is the correct answer.
Explanation:
Whether an acid is weak or strong it will cause harm if it comes in direct contact with the skin, eyes or mouth etc.
Thus, in order to prevent oneself, it is advised to wear a lab coat while working in laboratory as acids break down fabrics and can cause burns if the acids are strong.
Hence, a lab coat acts as a protective layer on the clothes so that even if acid falls on it then it might not reach the skin immediately and on time prevention can be taken.
