The essay will highlight the fact that for every simple machine, there is always friction involved. As per the law of conservation of energy, the energy input to a system is equivalent to the energy output. Some of this output is in the form of friction, which is not useful. As the moving parts in a machine increase, it becomes more complex and more friction is generated between its parts. Therefore, a complex machine ends up being less efficient.
Sadly, we're forced to answer the question without the benefit of the
list of choices, which, for some reason, you decided not to let us see.
Index of refraction of a substance =
(speed of light in vacuum) / (speed of light in the substance).
Any number greater than ' 1 ' can be an index of refraction. A number
less than ' 1 ' can't be . . . that would be saying that the speed of light
in this substance is greater than the speed of light in vacuum.
