For an ideal machine
(A) Output \[ = \]Input
(B) Output \[ > \]Input
(C) Output \[ < \] input
(D) Output \[ \geqslant \]input

Hint Understand what the term ideal means by. Ideal is a term that is given to anything that performs its actions perfectly without any errors or malfunctioning. Using this term ideal, relate to what a machine needs to do in order to be called ideal. Justify your answer.

Complete Step By Step Solution
A machine is defined as a combination of tools or an apparatus which consists of various mechanical frames and structures that are interrelated together, with each having separate functions to produce a definite work. The mechanical parts can be of two types, powered and non-powered.
Powered machines are machines which are given external power to complete a definite work. The power source can be manual, electric, air, water etc. Here the power that we provide to the machine can also be considered as input.
A machine is used to convert an indefinite input to usable output. Let’s see what an ideal machine is. Ideal machines are defined as machines where there is no loss in power due to any external factors and we were able to obtain the same power that we apply at the start.
So an ideal machine is said to have an efficiency of 100%. Efficiency is calculated as the ratio of output power is to input power. Now, when output is greater than input , the machine is said to have an efficiency greater than 100%. When input power is greater, the efficiency is very less. When the input power is equal to the output , we can say that the machine is ideal.

Hence, option(a) is the correct answer for given question.

Note Mechanical efficiency is defined as the capability of a machine to convert inputs to equivalent or varied outputs. In general, machine efficiency can be measured in terms of work done and power input. Mathematically it is given as the ratio between output work or power and input work or power.