NEET (UG) 2026 - Physics: Physics and Measurement Practice Test 50MCQs

NEET (UG) 2026 - Physics: Physics and Measurement Practice Test

Targeted 50 MCQ Practice Module focusing on: Units of Measurement, System of Units, SI Units, Fundamental & Derived Units, Least Count, Significant Figures, Errors in Measurement, Dimensions of Physical Quantities, and Dimensional Analysis with Applications.

Select your answers and click Submit Assessment Answers at the bottom to calculate your total score and review explanations.

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SECTION I: Units of Measurement & System of Units [Questions 1 to 10]

1. Which of the following is NOT a fundamental (base) physical quantity in the SI system?

Length Time Force Mass

Explanation: Force is a derived quantity (F = ma), expressed in terms of the fundamental quantities mass, length, and time.

2. In the CGS system of units, the fundamental units of length, mass, and time are respectively:

Centimetre, gram, second Metre, kilogram, second Foot, pound, second Metre, gram, minute

Explanation: CGS stands for Centimetre-Gram-Second, an early metric system of units.

3. The FPS system of units uses which of the following as its fundamental units?

Metre, kilogram, second Centimetre, gram, second Yard, pound, minute Foot, pound, second

Explanation: FPS (British/Imperial system) uses Foot for length, Pound for mass, and Second for time.

4. The SI base unit of luminous intensity is the:

Lumen Candela Lux Steradian

Explanation: Candela (cd) is the SI base unit for luminous intensity, one of the seven fundamental SI units.

5. The SI base unit for the amount of substance is the:

Gram Kilogram Mole Avogadro number

Explanation: The mole (mol) is the SI base unit for the amount of substance, containing Avogadro's number of elementary entities.

6. The system of units accepted internationally and used in scientific work worldwide today is called:

International System of Units (SI) CGS System FPS System MKS System only

Explanation: SI (Système International d'Unités), adopted in 1960, is the modern, internationally accepted metric system of measurement.

7. How many fundamental (base) units does the SI system consist of?

5 7 9 4

Explanation: SI has 7 base units: metre, kilogram, second, ampere, kelvin, mole, and candela.

8. The two supplementary units in the SI system, used for plane angle and solid angle, are:

Newton and joule Metre and candela Kelvin and mole Radian and steradian

Explanation: Radian (plane angle) and steradian (solid angle) were traditionally treated as supplementary SI units and are dimensionless.

9. The unit "radian", used to measure plane angle, is classified as a:

Dimensionless (supplementary) unit Fundamental unit Derived unit with dimensions CGS unit only

Explanation: Radian is defined as arc length divided by radius (both lengths), so it is a dimensionless ratio.

10. In the MKS system of units, length, mass, and time are measured respectively in:

Centimetre, gram, second Foot, pound, second Metre, kilogram, second Metre, gram, minute

Explanation: MKS stands for Metre-Kilogram-Second, the metric predecessor upon which the modern SI system is largely based.

SECTION II: SI Units, Fundamental & Derived Units [Questions 11 to 20]

11. The SI unit of force is the:

Joule Newton Watt Pascal

Explanation: The newton (N) is the SI unit of force, defined as kg·m·s⁻², named after Sir Isaac Newton.

12. Which of the following is a derived unit, not a base SI unit?

Newton Kelvin Ampere Candela

Explanation: Newton is derived from the base units kilogram, metre, and second, unlike kelvin, ampere, and candela which are base SI units.

13. The SI unit of pressure is the:

Newton Joule Watt Pascal

Explanation: Pascal (Pa) equals one newton per square metre (N/m²) and is the SI derived unit of pressure and stress.

14. The SI unit of work and energy is the:

Newton Watt Joule Erg

Explanation: The joule (J) is the SI derived unit for energy, work, and heat, equal to 1 N·m = 1 kg·m²·s⁻².

15. The SI unit of power is the:

Joule Watt Newton Coulomb

Explanation: Watt (W) is the SI unit of power, defined as one joule of energy transferred per second (J/s).

16. The SI unit of electric charge is the:

Coulomb Ampere Volt Ohm

Explanation: Coulomb (C) is the SI derived unit of electric charge, equal to the charge transported by a current of one ampere in one second.

17. The SI unit of frequency is the:

Radian per second Watt Joule Hertz

Explanation: Hertz (Hz) is the SI unit of frequency, equal to one cycle (event) per second, and has dimensions of T⁻¹.

18. Among the following, which is a fundamental (base) quantity along with its correct SI unit?

Velocity - metre per second Force - newton Thermodynamic temperature - kelvin Energy - joule

Explanation: Thermodynamic temperature (kelvin) is one of the seven SI base quantities; velocity, force, and energy are all derived quantities.

19. The SI base unit for electric current is the:

Coulomb Ampere Volt Farad

Explanation: Ampere (A) is the SI base unit of electric current, one of the seven fundamental SI units.

20. Which of the following pairs of fundamental quantity and its correct SI unit is properly matched?

Mass - kilogram Pressure - kilogram Length - newton Time - joule

Explanation: Mass is a fundamental quantity, and its correct SI base unit is the kilogram (kg).

SECTION III: Least Count & Significant Figures [Questions 21 to 30]

21. The least count of a Vernier Caliper is calculated as:

Pitch divided by number of circular scale divisions Sum of one Main Scale Division and one Vernier Scale Division Value of one Main Scale Division minus one Vernier Scale Division Number of Vernier divisions multiplied by Main Scale Division

Explanation: Least Count of a Vernier Caliper = 1 Main Scale Division (MSD) − 1 Vernier Scale Division (VSD).

22. The least count of a Screw Gauge (Micrometer) is given by:

Pitch of the screw ÷ Number of divisions on circular scale Number of divisions on circular scale ÷ Pitch of the screw 1 MSD − 1 VSD Pitch multiplied by the number of circular scale divisions

Explanation: Least Count of Screw Gauge = Pitch / Total number of divisions on the circular (head) scale.

23. If the pitch of a screw gauge is 1 mm and it has 100 divisions on its circular scale, its least count is:

0.1 mm 0.01 mm 1 mm 100 mm

Explanation: Least Count = Pitch / No. of circular divisions = 1 mm / 100 = 0.01 mm.

24. The number of significant figures in the measurement 0.00500 is:

3 5 6 2

Explanation: Leading zeros are not significant, but trailing zeros after a decimal point are significant. So 0.00500 has 3 significant figures: 5, 0, 0.

25. According to the rules of significant figures, all zeros occurring between two non-zero digits are:

Never significant Significant only in scientific notation Significant only if after decimal point Always significant

Explanation: Zeros between two non-zero digits (e.g., in 1005) are always counted as significant figures.

26. In multiplication or division of measured quantities, the final result should be rounded off to have significant figures equal to:

The largest number of significant figures among the operands The smallest number of significant figures among the operands The sum of significant figures of all operands Always exactly 3 significant figures

Explanation: In multiplication/division, the result is rounded to the number of significant figures of the operand with the fewest significant figures.

27. In addition or subtraction of measured quantities, the result should be rounded off according to:

The number with the most significant figures The average number of significant figures The least number of decimal places among the operands The greatest number of decimal places among the operands

Explanation: In addition/subtraction, the result should retain only as many decimal places as the term with the fewest decimal places.

28. The number of significant figures in the measured value 6.320 is:

2 3 5 4

Explanation: All non-zero digits (6, 3, 2) plus the trailing zero after the decimal point are significant, giving 4 significant figures.

29. The least count of a measuring instrument represents:

The smallest value that can be accurately measured using that instrument The largest value the instrument can measure The zero error of the instrument The total number of divisions on the main scale

Explanation: Least count is the smallest measurement that an instrument can accurately resolve or read.

30. To express a measured number like 100 without ambiguity about its significant figures, it is best written in:

Roman numerals Scientific (exponential) notation, e.g., 1.00 × 10² Fraction form Percentage form

Explanation: Scientific notation removes ambiguity about trailing zeros; 1.00 × 10² clearly shows 3 significant figures.

SECTION IV: Errors in Measurement [Questions 31 to 40]

31. Errors that arise due to faulty instrument calibration, imperfect experimental technique, or personal bias of the observer are called:

Systematic errors Random errors Gross errors only Least count errors only

Explanation: Systematic errors occur due to identifiable, consistent causes such as instrumental defects, imperfect technique, or personal errors, and they tend to occur in a definite direction.

32. Random errors in measurement arise due to unpredictable fluctuations in conditions and are best minimized by:

Using a costlier instrument only Ignoring the smallest readings Taking a large number of readings and calculating their arithmetic mean Taking only a single very careful reading

Explanation: Random errors, being unpredictable in direction and magnitude, are minimized by repeating the observation many times and averaging the results.

33. The absolute error in a single measurement is defined as:

The percentage difference between two readings The magnitude of the difference between the true (mean) value and the individual measured value The ratio of mean absolute error to mean value The least count of the instrument used

Explanation: Absolute error (Δa) = |mean value (a_mean) − individual measured value (aᵢ)|.

34. Relative error (fractional error) in a measured quantity is defined as:

Absolute error multiplied by 100 Mean value divided by absolute error Sum of all absolute errors Mean absolute error divided by the mean value of the quantity

Explanation: Relative error = (Mean absolute error) / (Mean value), a dimensionless ratio expressing error relative to the measured quantity.

35. Percentage error in a measurement is obtained by:

Multiplying the relative error by 100 Dividing the absolute error by 100 Adding the absolute error to the mean value Squaring the relative error

Explanation: Percentage error = Relative error × 100%.

36. When two quantities are added or subtracted, the resulting absolute error in the sum or difference is:

The difference of the two individual absolute errors Independent of the individual errors The sum of the individual absolute errors The product of the individual absolute errors

Explanation: For both addition and subtraction of measured quantities, the absolute errors of each quantity simply add up to give the maximum possible error in the result.

37. When two quantities are multiplied or divided, the resultant relative (fractional) error is:

The product of the two individual relative errors The sum of the individual relative errors Always zero The difference of the individual relative errors

Explanation: In multiplication and division, the maximum relative errors of the individual quantities add together to give the relative error in the result.

38. If a physical quantity Z is given by Z = A^n, the relative error in Z in terms of relative error in A is:

n times the relative error in A The relative error in A divided by n Independent of n Equal to the relative error in A regardless of power

Explanation: For Z = Aⁿ, ΔZ/Z = n(ΔA/A); the relative error gets multiplied by the power to which the quantity is raised.

39. Zero error present in an instrument (such as a vernier caliper or screw gauge not reading zero when jaws are closed) is classified as a:

Random error Gross error only Personal error Systematic (instrumental) error

Explanation: Zero error is a consistent, repeatable instrumental defect, hence classified as a systematic error, and it must be corrected for in every reading.

40. The error that arises in a measurement purely due to the limited resolving power (least count) of the measuring instrument is known as:

Gross error Least count error Personal error Environmental error

Explanation: Least count error is associated with the resolution/least count of the instrument and is a type of random error that can be minimized by using instruments of higher precision and taking multiple readings.

SECTION V: Dimensions & Dimensional Analysis [Questions 41 to 50]

41. The dimensional formula of force is:

[ML²T⁻²] [MLT⁻¹] [MLT⁻²] [ML⁻¹T⁻²]

Explanation: Force = mass × acceleration = M × (LT⁻²) = [MLT⁻²].

42. The dimensional formula of work (or energy) is:

[ML²T⁻²] [MLT⁻²] [ML²T⁻³] [ML⁻¹T⁻²]

Explanation: Work = Force × displacement = [MLT⁻²] × [L] = [ML²T⁻²]. Energy has the same dimensions as work.

43. The dimensional formula of power is:

[ML²T⁻²] [MLT⁻²] [ML⁻¹T⁻²] [ML²T⁻³]

Explanation: Power = Work/time = [ML²T⁻²] / [T] = [ML²T⁻³].

44. The dimensional formula of pressure is:

[MLT⁻²] [ML⁻¹T⁻²] [ML²T⁻²] [ML⁻²T⁻²]

Explanation: Pressure = Force/Area = [MLT⁻²] / [L²] = [ML⁻¹T⁻²].

45. Which of the following is a dimensionless physical quantity?

Strain Force Momentum Pressure

Explanation: Strain is the ratio of change in dimension to original dimension (both lengths), making it dimensionless, like angle and refractive index.

46. The Principle of Homogeneity of Dimensions states that a physical equation is dimensionally correct only if:

All terms have the same numerical value The equation contains no more than three terms The dimensions of all terms on both sides of the equation are the same The equation is derived experimentally

Explanation: The Principle of Homogeneity requires that every term added, subtracted, or equated in a physical equation must have identical dimensions.

47. A major limitation of the method of dimensional analysis is that it:

Cannot be used to check the correctness of an equation Cannot determine dimensionless proportionality constants in a relation Cannot be applied to derive relations among physical quantities Cannot be used to convert units from one system to another

Explanation: Dimensional analysis cannot determine dimensionless constants (like 1/2, π, or other pure numbers) appearing in a physical formula.

48. The dimensional formula of the Universal Gravitational Constant (G) is:

[ML³T⁻²] [M⁻¹L³T⁻¹] [MLT⁻²] [M⁻¹L³T⁻²]

Explanation: From F = Gm₁m₂/r², G = Fr²/(m₁m₂), giving dimensions [M⁻¹L³T⁻²].

49. The dimensional formula of Planck's constant (h) is the same as that of:

Angular momentum Force Pressure Power

Explanation: Planck's constant, from E = hν, has dimensions [ML²T⁻¹], identical to the dimensional formula of angular momentum.

50. Which of the following is NOT a valid application/use of dimensional analysis?

Checking the dimensional correctness of a given physical equation Converting a physical quantity from one system of units to another Determining the exact numerical (dimensionless) constant in a derived formula Deriving a possible relationship among physical quantities

Explanation: Dimensional analysis can check equations, convert units, and help derive relations, but it cannot determine dimensionless numerical constants in a formula.

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