Accuracy, Precision & Order of Magnitude — MH-CET Physics MCQs with Solutions
Free MH-CET Physics Accuracy, Precision & Order of Magnitude MCQs with step-by-step solutions (20 questions). Part of Units and Measurements (Std 11). Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Accuracy, Precision & Order of Magnitude · easy · theory
The accuracy of a measurement refers to:
A. How closely repeated measurements agree with one another
B. The number of readings taken
C. How close the measured value is to the true value ✓ Correct
D. The cost of the instrument used
Solution: Accuracy is about correctness; precision is about reproducibility.
Q2 — Accuracy, Precision & Order of Magnitude · easy · theory
The precision of a measurement refers to:
A. The presence of systematic errors
B. How closely repeated measurements agree with one another ✓ Correct
C. How close the measurement is to the true value
D. The range of the instrument
Solution: It is governed largely by the least count of the instrument.
Q3 — Accuracy, Precision & Order of Magnitude · medium · theory
A set of measurements can be:
A. Neither precise nor accurate under any circumstances
B. Highly precise only if it is also accurate
C. Accurate only if it is imprecise
D. Highly precise yet inaccurate, if a systematic error is present ✓ Correct
Solution: A screw gauge with a zero error gives tightly clustered but consistently wrong readings.
Q4 — Accuracy, Precision & Order of Magnitude · medium · theory
The order of magnitude of a quantity is:
A. The number of significant figures it contains
B. Its numerical value in SI units
C. Its percentage error
D. The power of ten nearest to the quantity when written in scientific notation ✓ Correct
Solution: It gives a rough idea of size, useful when only a rapid comparison is needed.
Q5 — Accuracy, Precision & Order of Magnitude · medium · theory
The parallax method is used to measure:
A. The distances of nearby stars and planets ✓ Correct
B. The charge on an electron
C. The mass of the Earth
D. The speed of sound in air
Solution: The apparent shift of a nearby object against a distant background gives its distance by simple geometry.
Q6 — Accuracy, Precision & Order of Magnitude · easy · theory
Writing a quantity in scientific notation as $a \times 10^b$ requires that:
A. $b$ be positive
B. $0 < a < 1$
C. $a$ be an integer
D. $1 \le a < 10$ ✓ Correct
Solution: This standard form makes the number of significant figures unambiguous.
Q7 — Accuracy, Precision & Order of Magnitude · medium · theory
The number of significant figures quoted in a result indicates its:
A. Precision ✓ Correct
B. Order of magnitude
C. Accuracy
D. Systematic error
Solution: A result written to four figures claims greater precision than one written to two.
Q8 — Accuracy, Precision & Order of Magnitude · easy · theory
A vernier callipers is more precise than an ordinary metre scale because it has:
A. A longer measuring range
B. No zero error
C. A heavier construction
D. A smaller least count ✓ Correct
Solution: Its least count of $0.01\text{ cm}$ is ten times finer than the $0.1\text{ cm}$ of a metre scale.
Q9 — Accuracy, Precision & Order of Magnitude · medium · numerical
The least count of a vernier callipers with $10$ vernier divisions matching $9$ main scale divisions of $1\text{ mm}$ each is:
A. $0.01\text{ cm}$ ✓ Correct
B. $0.1\text{ cm}$
C. $1\text{ cm}$
D. $0.001\text{ cm}$
Solution: Least count $= \dfrac{1\text{ mm}}{10} = 0.1\text{ mm} = 0.01\text{ cm}$.
Q10 — Accuracy, Precision & Order of Magnitude · medium · numerical
A screw gauge has a pitch of $1\text{ mm}$ and $100$ divisions on its circular scale. Its least count is:
A. $0.0001\text{ cm}$
B. $0.01\text{ cm}$
C. $0.001\text{ cm}$ ✓ Correct
D. $0.1\text{ cm}$
Solution: Least count $= \dfrac{\text{pitch}}{\text{number of divisions}} = \dfrac{1}{100} = 0.01\text{ mm} = 0.001\text{ cm}$.
Q11 — Accuracy, Precision & Order of Magnitude · medium · numerical
A screw gauge has a pitch of $0.5\text{ mm}$ and $50$ divisions on its circular scale. Its least count is:
A. $0.01\text{ mm}$ ✓ Correct
B. $0.05\text{ mm}$
C. $0.1\text{ mm}$
D. $0.001\text{ mm}$
Solution: Least count $= \dfrac{0.5}{50} = 0.01\text{ mm}$.
Q12 — Accuracy, Precision & Order of Magnitude · hard · numerical
In a vernier callipers, $20$ vernier divisions coincide with $19$ main scale divisions of $1\text{ mm}$ each. The least count is:
A. $0.05\text{ mm}$ ✓ Correct
B. $0.1\text{ mm}$
C. $0.5\text{ mm}$
D. $0.01\text{ mm}$
Solution: Least count $= 1\text{ MSD} - 1\text{ VSD} = 1 - \dfrac{19}{20} = 0.05\text{ mm}$.
Q13 — Accuracy, Precision & Order of Magnitude · hard · numerical
A vernier reading shows a main scale reading of $1.2\text{ cm}$ with the $6^{\text{th}}$ vernier division coinciding. If the least count is $0.01\text{ cm}$, the measurement is:
A. $7.2\text{ cm}$
B. $1.26\text{ cm}$ ✓ Correct
C. $1.06\text{ cm}$
D. $1.86\text{ cm}$
Solution: Reading $= 1.2 + 6 \times 0.01 = 1.26\text{ cm}$.
Q14 — Accuracy, Precision & Order of Magnitude · hard · numerical
A screw gauge shows a main scale reading of $2\text{ mm}$ with the $45^{\text{th}}$ circular division coinciding. If the least count is $0.01\text{ mm}$, the measurement is:
A. $2.045\text{ mm}$
B. $2.45\text{ mm}$ ✓ Correct
C. $47\text{ mm}$
D. $6.5\text{ mm}$
Solution: Reading $= 2 + 45 \times 0.01 = 2.45\text{ mm}$.
Q15 — Accuracy, Precision & Order of Magnitude · medium · numerical
The order of magnitude of $3 \times 10^8$ is:
A. $9$
B. $10$
C. $3$
D. $8$ ✓ Correct
Solution: The mantissa $3$ is less than $5$, so the exponent stands as the order of magnitude.
Q16 — Accuracy, Precision & Order of Magnitude · hard · numerical
The order of magnitude of $7.2 \times 10^5$ is:
A. $5$
B. $7$
C. $4$
D. $6$ ✓ Correct
Solution: Since the mantissa $7.2$ exceeds $5$, the number is nearer $10^6$ than $10^5$.
Q17 — Accuracy, Precision & Order of Magnitude · medium · numerical
The order of magnitude of $2.1 \times 10^{-3}$ is:
A. $-4$
B. $3$
C. $-2$
D. $-3$ ✓ Correct
Solution: The mantissa is below $5$, so the order of magnitude is the exponent itself.
Q18 — Accuracy, Precision & Order of Magnitude · easy · numerical
The diameter of an atom is about $10^{-10}\text{ m}$. Its order of magnitude is:
A. $-12$
B. $10$
C. $-10$ ✓ Correct
D. $-8$
Solution: The quantity is already a pure power of ten.
Q19 — Accuracy, Precision & Order of Magnitude · medium · numerical
Of two results, $2.5\text{ cm}$ and $2.500\text{ cm}$, the more precise is:
A. Neither can be compared
B. $2.5\text{ cm}$
C. Both are equally precise
D. $2.500\text{ cm}$, having four significant figures ✓ Correct
Solution: More significant figures assert a finer measurement.
Q20 — Accuracy, Precision & Order of Magnitude · medium · numerical
A vernier callipers has a least count of $0.01\text{ cm}$. The maximum uncertainty in a single reading is:
A. $0.1\text{ cm}$
B. $0.001\text{ cm}$
C. Zero
D. $0.01\text{ cm}$ ✓ Correct
Solution: A measurement cannot be quoted more finely than the least count of the instrument.