9702_s22_qp_13 Question 1

 Which pair of quantities are physical quantities? 

A charge and ampere 

B efficiency and kilogram 

C pascal and strain 

D period and potential difference

ANSWER: D

The Physics behind the answer:

• Physical quantities are those properties that we may be able to measure. A unit on the other hand is the one quantity where we compare any other quantities. 
• For example, saying that "my sister is 5 Physics books tall" you are describing a quantity i.e. height and comparing it with the unit Physics book. This is to say that if you know the length of a Physics book, then the height of the sister is 5 times of that. In everyday usage, however, we do not use the Physics book as a unit. Instead, we use a metre, centimetre, inches, feet, etc.. We say 5 metre or 5 cm or 5 feet, and others.
• You should see that units are written after the number describing a physical quantity. 
• Among the options, only D has both physical quantities - period and potential difference - of units second and volts, respectively.