Question

Which row shows a quantity and an incorrect unit?

Quantity	Unit
Efficiency	No unit
Moment of Force	Newton Meter
Momentum	Newton Second
Work Done	Joule

Answer 1

Hint: For this we have to know about physical quantities with their units. In physics every quantity like mass, momentum, time, energy, etc. all have different meanings with different units. Remember the units and check the question for the incorrect one.

Complete step by step solution:
Efficiency means a pinnacle level of execution that utilizes minimal measure of contributions to accomplish the worthiest measure of output. Efficiency requires decreasing the quantity of superfluous resources used to create a given yield including individual time and energy. It is a quantifiable idea that can be resolved utilizing the proportion of helpful yield to add up to enter. It limits the misuse of assets, meaning ratio of output to input. Therefore, it does not have any units. for example, physical materials, energy, and time while achieving the ideal yield.

Moment is an articulation including the result of a separation and physical quantity, and in this way, it represents how the physical quantity is found or organized. Moments are typically characterized concerning a fixed reference point; they manage physical amounts situated at some separation comparative with that reference point. For instance, the moment of force, frequently called torque, is the result of a force on an article and the distance from the reference highlights the item. On a basic level, any physical amount can be increased by a distance to deliver a moment. The SI unit for the moment is the Newton meter.

Momentum, result of the mass of a molecule and its velocity. it is a vector quantity; i.e., it has both magnitude and direction. Isaac Newton's second law of motion expresses that the time rate of momentum of energy is equivalent to the force following up on the molecule. Its SI unit is kilogram meter per second.

Work- Work is done when motion is produced by a body. It is the product of force and distance moved by body in the direction of force. Work is the scalar product of force and displacement. Its unit is joule.

Therefore, Option (C) is the answer as its unit is given incorrectly.

Note: You need to memorize the units of all physical quantities. Moreover, memorizing their units in SI as well as the cgs system will be a plus point. The cgs system of units uses centimeters, grams and seconds to measure quantities. Though it's easy to convert units from Si to cgs, memorizing them is always beneficial as it saves time.