Answer : The correct option is, (D) A machine does 400 joules of work in 5 seconds.
Explanation :
Power : It is defined a the rate of doing work per unit time.
Formula used :
[tex]P=\frac{w}{t}[/tex]
where,
P = power
w = work done
t = time
Now we have to determine the rate of power for the following options.
(A) A machine does 200 joules of work in 10 seconds.
[tex]P=\frac{200}{10}=20W[/tex]
(B) A machine does 400 joules of work in 10 seconds.
[tex]P=\frac{400}{10}=40W[/tex]
(C) A machine does 200 joules of work in 5 seconds.
[tex]P=\frac{200}{5}=40W[/tex]
(D) A machine does 400 joules of work in 5 seconds.
[tex]P=\frac{400}{5}=80W[/tex]
From this we conclude that, a machine does 400 joules of work in 5 seconds has the highest rate of power.
Hence, the correct option is, (D)
