Physics And Measurement Important Questions for NEET Physics - 2026

1. Multiple choice questions.

Q1. Which of the following pairs are both SI base units?

• (a) meter, kilogram
• (b) joule, second
• (c) newton, meter
• (d) kilogram, newton

Answer: (a) meter, kilogram

Q2. The least count of a vernier caliper is:

• (a) The smallest length measured by its main scale
• (b) Its accuracy limit, usually 1 mm
• (c) The smallest length measured by the vernier scale
• (d) The difference between one main scale and one vernier scale division

Answer: (d) The difference between one main scale and one vernier scale division

Q3. A quantity which has both magnitude and direction but does not follow the triangle law of addition is:

• (a) Scalar
• (b) Vector
• (c) Polar vector
• (d) Axial vector

Answer: (d) Axial vector

Q4. Which one of the following is a dimensionless quantity?

• (a) Strain
• (b) Work
• (c) Volume
• (d) Power

Answer: (a) Strain

Q5. If $x = a + bt + ct^2$, the dimension of $c$ is:

• (a) $[L]$
• (b) $[L T^{-1}]$
• (c) $[L T^{-2}]$
• (d) $[T^{-2}]$

Answer: (c) $[L T^{-2}]$

2. Very Short Answer (VSA).

Q1. Define least count.

Answer: Least count is the smallest value that can be accurately measured by an instrument, indicating its precision.

Q2. What is the SI unit of luminous intensity?

Answer: The SI unit of luminous intensity is the candela (cd).

Q3. Name a fundamental unit and a derived unit.

Answer: The meter (m) is a fundamental unit, while the newton (N) is a derived unit.

Q4. What is the dimension of velocity?

Answer: The dimension of velocity is $[L T^{-1}]$.

Q5. Define accuracy in measurement.

Answer: Accuracy is how close a measured value is to the true value of the quantity measured.

3. Short Answer Questions.

Q1. Explain why measurement errors are unavoidable and classify their types.

Answer: Measurement errors are unavoidable due to limitations in instruments, human error, and experimental conditions. Errors are classified as systematic errors (which have a definite cause, like faulty calibration) and random errors (which occur unpredictably due to minor variations during experiments).

Q2. Discuss the role of significant figures in experimental physics.

Answer: Significant figures show the precision of a measured value. While reporting results, the number of significant figures reflects the reliability of measurements, helps indicate measurement accuracy, and avoids the illusion of high precision when it is not justified by the instrument.

Q3. How is dimensional analysis useful in checking the correctness of equations?

Answer: Dimensional analysis ensures that both sides of a physical equation have the same dimensions, indicating correctness. It helps verify equations, derive new relationships, and convert units, as equations with inconsistent dimensions are physically invalid.

Q4. The period of a simple pendulum is given by $T = 2\pi\sqrt{\dfrac{l}{g}}$. Using dimensional analysis, check if the formula is consistent.

Answer:

1. Dimension of $l$ is $[L]$, $g$ is $[L T^{-2}]$.
2. So, $\frac{l}{g} = [L][L^{-1}T^{2}] = [T^2]$
3. $\sqrt{[T^2]} = [T]$, and $2\pi$ is dimensionless, so $T$ is $[T]$.
4. Both sides have dimension $[T]$; so, the formula is dimensionally consistent.

Q5. State two applications of dimensional analysis in physics.

Answer: Dimensional analysis is used for:

• Checking the correctness of physical equations
• Deriving relationships among physical quantities and converting units between different systems

4. True or False Questions.

Q1. The SI unit of force is joule.

Answer: False

Q2. All errors in measurements are random.

Answer: False

Q3. A quantity with dimensions $[M^0L^0T^0]$ is dimensionless.

Answer: True

Q4. The ampere is a fundamental SI unit.

Answer: True

Q5. Instrumental errors arise due to incorrect readings recorded by the observer.

Answer: False

3. Fill in the Blanks Questions.

Q1. The SI unit of pressure is ________.

Answer: pascal

Q2. The ________ is the smallest division on the main scale of an instrument.

Answer: least count

Q3. In reporting a measurement, the last digit is called the ________ digit.

Answer: doubtful

Q4. The dimensional formula of energy is ________.

Answer: $[M L^2 T^{-2}]$

Q5. The number of fundamental units in the SI system is ________.

Answer: seven

Why Learning Physics and Measurement Matters for NEET Students

Mastering units and dimensions builds a clear foundation for NEET Physics. It enables students to solve problems correctly, recognize physical quantities, and choose the right methods for measurements. These fundamental concepts greatly support confident preparation for competitive exams like NEET.

Understanding least count and significant figures helps every NEET aspirant reduce errors and report results accurately. These topics are often asked in exams, making it easier for students to avoid mistakes and improve their scoring potential in Physics.

Solving questions on dimensional analysis and measurement error prepares students for real NEET scenarios. These skills allow quick verification of answers, offer clarity in concepts, and strengthen every student’s analytical thinking for NEET 2026 with Vedantu’s expert guidance.