Question

The two input terminals of an op-amp are labelled as:
A) High and low
B) Positive and negative
C) Inverting and non-inverting
D) Differential and non-differential

Answer 1

Hint: To solve this question all you need is some basic knowledge about op-amp. An op-amp or operational amplifier, is a three-terminal device, which has two inputs and one output port. They used majorly in conditioning or filtering of signals or to perform mathematical operations such as addition, subtraction, etc.

Complete step by step answer:
To reach at the answer, even basic knowledge about op-amps or operational amplifiers is enough. As told in the hint section, an operational amplifier is a linear device which owns all the properties which make it a really good, near-perfect DC amplification device. Basically, an op-amp is a voltage amplification device which is supposed to be used with components which give external feedback like capacitors, resistors between its output and input terminals. These external feedback components help in determining the net resultant function or the operation of the amplifier and through considering all the varying feedback types, resistive, capacitive or both, it can perform a wide set of operations, as suggested by the name of the device as Operational Amplifier.
As we told in the hint section, op-amp is a three-terminal device. Out of the three terminals, two are for input and the remaining one is the output port. Out of the two input ports, one is marked with a negative sign. This input is known as the Inverting input. On the contrary, the other input is marked with a positive sign, which is known as the Non-inverting input.

Hence, we can see that the correct option is the option which has Inverting and Non-inverting inputs, i.e. option (C) is the correct answer.

Note: Many students tick the option (B) as the correct one since the inputs are marked with a positive and negative sign, which is wrong since the question has asked about the labels of the inputs, which is nothing but Inverting and Non-inverting.