Units and Measurements PYQ Practice for NEET
Units and Measurements is a compact but important NEET Physics chapter. It tests accuracy, dimensional reasoning and numerical rules that also help in many other Physics chapters.
Use this page to revise the concepts first and then attempt the PYQ-style questions without opening their solutions. After each answer, identify whether your mistake came from a formula, a unit conversion, a significant-figure rule or error propagation.
Topics to Revise Before Practice
These concepts cover the most common question patterns from Units and Measurements.
SI Units
Know the seven SI base units and how derived units are written using them.
Dimensions
Write dimensional formulae for force, energy, pressure, momentum, impulse and constants.
Dimensional Analysis
Check equations, compare options and convert a unit systematically.
Significant Figures
Apply zero rules, rounding rules and decimal-place rules correctly.
Error Analysis
Calculate absolute, relative and percentage errors in measured quantities.
Combination of Errors
Add percentage errors correctly for products, quotients and powers.
Units and Measurements Formula Revision
Revise these formulas before attempting the practice set.
NEET Physics Units and Measurements PYQ Practice Questions
Attempt every question on your own before revealing the solution.
Which of the following pairs does NOT have the same dimensional formula?
Show answer and explanation
Answer: C. Force has dimensions \([M L T^{-2}]\), while pressure is force per unit area and has dimensions \([M L^{-1} T^{-2}]\). The other listed pairs have the same dimensions.
A student records the length of a rod as 3.50 cm. The number of significant figures in this measurement is:
Show answer and explanation
Answer: C. The digits 3 and 5 are significant, and the zero after the decimal point is also significant. Therefore, 3.50 has three significant figures.
The radius of a sphere is measured with a 2% error. The maximum percentage error in its calculated volume is:
Show answer and explanation
Answer: C. Volume is proportional to \(r^3\). Hence the maximum percentage error is \(3 \times 2\% = 6\%\).
The dimensional formula of the universal gravitational constant \(G\) is:
Show answer and explanation
Answer: A. From \(F = Gm_1m_2/r^2\), we get \([G] = [F][r^2][M^{-2}] = [M^{-1} L^3 T^{-2}]\).
A quantity \(X = \frac{A^2B}{C}\). Percentage errors in \(A\), \(B\) and \(C\) are 1%, 2% and 3% respectively. The maximum percentage error in \(X\) is:
Show answer and explanation
Answer: D. Maximum percentage error = \(2(1\%) + 1(2\%) + 1(3\%) = 7\%\).
If 1 newton equals \(10^5\) dyne, then 1 joule is equal to:
Show answer and explanation
Answer: C. One joule is one newton-metre. Since \(1\,N = 10^5\) dyne and \(1\,m = 10^2\) cm, \(1\,J = 10^7\) dyne-cm = \(10^7\) erg.
The least count of an instrument represents:
Show answer and explanation
Answer: B. Least count is the smallest value that an instrument can measure or read directly. A smaller least count generally allows more precise measurement.
When 12.11 and 18.0 are added, the correctly reported result is:
Show answer and explanation
Answer: B. For addition, the answer must have the same number of decimal places as the term with the fewest decimal places. Since 18.0 has one decimal place, the result is 30.1.
Continue Your NEET Physics Preparation
After revising this chapter, attempt chapter-wise tests and analyse every incorrect answer. Focus on the exact rule or concept that caused each mistake.
Explore Available Free TestsHow to Practise This Chapter
- Memorise SI base units and frequently used dimensional formulae.
- Practise converting a Physics formula into dimensions step by step.
- Solve significant-figure questions separately until rounding rules become automatic.
- Use the exponent of each quantity while calculating maximum percentage error.
- Review solutions only after choosing an answer independently.
Common mistakes to avoid
- Counting leading zeros as significant figures.
- Mixing up force and pressure dimensions.
- Forgetting to multiply percentage error by the power of a variable.
- Assuming dimensional consistency proves a formula is physically complete.
- Reading explanations before making an attempt.
NEET Units and Measurements PYQ Practice FAQs
Are these exact official NEET previous-year questions?
No. These are original practice questions designed in a NEET PYQ-style format. Check official sources separately for exact previous-year papers.
Which topics are most important in Units and Measurements?
Dimensions, SI units, significant figures, least count, percentage error and combination of errors are key areas for revision.
How can dimensional analysis help in NEET Physics?
It can check whether an equation is dimensionally consistent, help with unit conversion and eliminate incorrect options. It cannot determine dimensionless constants.
How should I handle error-propagation questions?
First identify whether quantities are multiplied, divided or raised to a power. Then add maximum percentage errors after multiplying each error by its power.