Answer:
v = 2 m/s
Explanation:
The object moves 20 m in 10 s initially. Then it remains at rest for 20 s. It is required to find the average speed of the object.
Fro 10 s it covers 20 m. For that time, speed is :

For 20 s, it was at rest means distance covered is 0. So, speed is 0.
The average speed of the object is equal to the sum of speed for 10 s and for 20 s i.e.
v = 2 m/s + 0 = 2 m/s
So, the average speed of the object is 2 m/s.
This is a riddle meant to have a humorous effect.
So, what did they call the bug that the astronauts brought back from the moon? - A lunatic.
The word lunatic consists of lunar (relating to the Moon) and tick, which is a type of an insect.
As we know that

here we know that


now by the above formula we will have



Be because it’s the answer
For all antinodal positions we know that

now we also know the relation between phase difference and path difference

now we will have

now from above equation we will have

now for the first anti node position
N = 1

Option D is correct