watts = work per second.
work is mgh = 3x10x50=1500
watts out = 1500
Watts used = 2000
eff=1500/2000=75%
I think it’s output because output work is work done by a machine
Explanation:
Given that,
The optical power of the equivalent single lens is 45.4 diopters.
(a) The relationship between the focal length and the focal length is given by:


f = 0.022 m
or
f = 2.2 cm
(b) We need to find how far in front of the retina is this "equivalent lens" located. It is given by using lens formula as :

Here, u = infinity

v = 2.2 cm
So, at 2.2 cm in front of the retina is this "equivalent lens" located.
Hence, this is the required solution.
Answer:
D
Explanation:
1.) The reaction is at dynamic equilibrium.
A: Nitrogen and hydrogen combine at the same rate that ammonia breaks down.
2.) Which statement about the reaction is necessarily correct?
A: Both calcium carbonate and sodium carbonate are being produced.
3.) Both calcium carbonate and sodium carbonate are being produced.
A: The reaction is reversible.
4.) What is the fastest motion that can be measured in any frame of reference?
A: 300,000 km/s
5.) Two people are on a train that is moving at 10 m/s north. They are walking 1 m/s south relative to the train. Relative to the ground, their motion is 9 m/s north.
Why are we able to use these motions to describe the motion relative to the ground?
A: The people are moving much slower than the speed of light so the ground acts as a frame of reference.
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