Noise is an unwanted signal which interferes with the original message signal and corrupts the parameters of the message signal. This alteration in the communication process, leads to the message getting altered. It is most likely to be entered at the channel or the receiver.
Explanation:
For question no 19
Force (F) = 20N
distance (d) = 5m
Work = F * d
= 20 * 5
= 100 J
Now
For question no 20
D. No matter how much force is applied the object must have motion for work to be done.
A particle smaller than an atom or cluster of small particles