Which of the following rules are used in choosing the repeating variables in dimensional analysis?
- ARepeating variable should include the dependent variable
- BRepeating variable should combine among themselves to form a dimensionless group
- CRepeating variable should contain at least one dimensionless parameter
- DRepeating variable should contain all the primary units used in describing the variables in the question.Correct
Solution
Concept
Rules for repeating variables
Step-by-step solution
1. They must include all primary dimensions and must not include the dependent variable.
Explanation
Repeating variables together contain M, L, T.
Why the other options are wrong
They must not form a dimensionless group.
Shortcut
All dimensions in; dependent out.
Correct answer: D) Repeating variable should contain all the primary units used in describing the variables in the question.