Physical Quantities and Measurement Quiz - ICSE Class 8 Science
Free practice quiz: Physical Quantities and Measurement (ICSE Class 8 Science). 53 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which of the following is a fundamental physical quantity?
- Velocity
- Force
- Mass
- Acceleration
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Answer: C. Mass
Fundamental physical quantities are those that cannot be defined in terms of other physical quantities. Mass, length, and time are examples of fundamental quantities. Velocity, force, and acceleration are derived quantities.
If an instrument has a negative zero error, the corrected reading is obtained by:
- Subtracting the zero error
- Adding the absolute value of the zero error
- Multiplying by the zero error
- Dividing by the zero error
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Answer: B. Adding the absolute value of the zero error
A negative zero error means the instrument reads lower than the actual value. To correct this, you need to add the magnitude (absolute value) of the negative zero error to the observed reading to get the true reading.
A measurement is considered accurate if it is:
- Repeatedly close to the same value
- Close to the true or accepted value
- Expressed with many significant figures
- Measured using a complex instrument
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Answer: B. Close to the true or accepted value
Accuracy refers to how close a measurement is to the actual or true value. Precision refers to the closeness of repeated measurements to each other.
If a measurement is 25.45 cm and the instrument has a least count of 0.1 cm, what is the uncertainty?
- ± 0.05 cm
- ± 0.1 cm
- ± 0.5 cm
- ± 1 cm
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Answer: A. ± 0.05 cm
The uncertainty is typically half of the least count. The least count here is 0.1 cm, so the uncertainty is $\frac{0.1 ext{ cm}}{2} = \pm 0.05 ext{ cm}$.
Which of the following is an example of a derived quantity?
- Mass
- Length
- Speed
- Time
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Answer: C. Speed
Speed is a derived quantity, defined as distance traveled per unit time (Speed = Distance / Time). Mass, length, and time are fundamental SI quantities.