B evaporation since the water is going up
The power of a machine depend on two factors are work and time.
Option C
<u>Explanation:</u>
In science, power defined as the amount of work done in a unit time. i.e. delivering work in a rate of time or energy supply, expressed in input of work or transmitted energy divided by the time interval (t) or W/t.
Example: Some work can be done in the long run with a low-power engine or in a short time with a motor with high performance. The equation for power can be given as


Answer:
22cm
Explanation:
focal length = 11cm
radius of curvature,r = 2f
r= 2 x 11
r=22cm
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 :

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.

(B) A machine does 400 joules of work in 10 seconds.

(C) A machine does 200 joules of work in 5 seconds.

(D) A machine does 400 joules of work in 5 seconds.

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)