Measurements and Errors Practice Questions
A-Levels · A-Level Physics · 145 free MCQs with instant results and detailed explanations.
145
Total
49
Easy
72
Medium
24
Hard
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Sample Questions from Measurements and Errors
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Q1
Easy
What is the basic unit of length in the SI system?
A.
Meter
B.
Centimeter
C.
Kilometer
D.
Millimeter
Show Answer & Explanation
Correct Answer: A
The basic unit of length in the SI system is the meter, defined as the distance light travels in vacuum in 1/299,792,458 seconds.
Q2
Easy
Which of the following instruments is best suited for measuring small lengths accurately?
A.
Ruler
B.
Caliper
C.
Tape Measure
D.
Protractor
Show Answer & Explanation
Correct Answer: B
A caliper is designed to measure small dimensions with high accuracy, allowing for precise measurements beyond the capacity of a ruler or tape measure.
Q3
Easy
A digital scale shows a mass reading of 50.0 kg. If the scale has an uncertainty of ยฑ0.1 kg, what is the range of the true mass?
A.
49.9 kg to 50.1 kg
B.
50.0 kg to 50.2 kg
C.
49.5 kg to 50.5 kg
D.
50.1 kg to 50.3 kg
Show Answer & Explanation
Correct Answer: A
The true mass range takes into account the uncertainty. With a reading of 50.0 kg and an uncertainty of ยฑ0.1 kg, the true mass can vary from 49.9 kg to 50.1 kg.
Q4
Medium
A ruler has a least count of 0.1 cm. If a measurement taken using this ruler is 5.7 cm, what is the maximum possible error in this measurement?
A.
ยฑ0.1 cm
B.
ยฑ0.01 cm
C.
ยฑ0.5 cm
D.
ยฑ0.05 cm
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Correct Answer: A
The least count indicates the smallest value the instrument can measure. Therefore, the maximum possible error is equal to the least count, which is ยฑ0.1 cm.
Q5
Medium
A mass of 2.0 kg is measured with an uncertainty of ยฑ0.05 kg. What is the percentage error in the measurement?
A.
2.5%
B.
5.0%
C.
10.0%
D.
1.0%
Show Answer & Explanation
Correct Answer: A
Percentage error is calculated as (absolute error / measured value) x 100%. Here, it's (0.05 kg / 2.0 kg) x 100% = 2.5%.
Q6
Medium
If a stopwatch has a precision of ยฑ0.1 seconds and a recorded time for a race is 25.6 seconds, what is the range of possible recorded times?
A.
25.5 to 25.7 seconds
B.
25.4 to 25.6 seconds
C.
25.6 to 25.8 seconds
D.
25.0 to 26.0 seconds
Show Answer & Explanation
Correct Answer: A
To find the range, subtract and add the precision to the recorded time. So, 25.6 - 0.1 = 25.5 and 25.6 + 0.1 = 25.7 seconds.
Q7
Medium
A student measures a length as 12.4 cm with a systematic error of +0.2 cm. What is the true length of the object?
A.
12.2 cm
B.
12.4 cm
C.
12.6 cm
D.
12.0 cm
Show Answer & Explanation
Correct Answer: C
To find the true length, account for the systematic error. So, true length = measured length - systematic error = 12.4 cm + 0.2 cm = 12.6 cm.
Q8
Hard
A metal rod is heated, causing it to expand. If the initial length of the rod is 2.0 m and the coefficient of linear expansion is 1.2 x 10^-5 /ยฐC, what will be the increase in length if the temperature rises by 50ยฐC?
A.
0.0012 m
B.
0.012 m
C.
0.06 m
D.
0.0024 m
Show Answer & Explanation
Correct Answer: A
The increase in length (ฮL) can be calculated using the formula ฮL = L0 ร ฮฑ ร ฮT. Here, L0 = 2.0 m, ฮฑ = 1.2 x 10^-5 /ยฐC, and ฮT = 50ยฐC. Thus, ฮL = 2.0 ร 1.2 x 10^-5 ร 50 = 0.0012 m.
Q9
Hard
A scientist measures the resistance of a resistor using a multimeter and finds it to be 100 ฮฉ with a possible error of ยฑ2 ฮฉ. If this resistor is used in a circuit with a 12V battery, what is the maximum possible current through the resistor?
A.
0.12 A
B.
0.10 A
C.
0.11 A
D.
0.14 A
Show Answer & Explanation
Correct Answer: A
To find the maximum current, use Ohm's law: I = V/R. The maximum resistance, considering the error, is 100 ฮฉ + 2 ฮฉ = 102 ฮฉ. Thus, the maximum current is I_max = 12V / 102ฮฉ = 0.1176 A, which rounds to 0.12 A.
Q10
Hard
A student measures the length of a metal rod using a ruler with a least count of 0.1 cm. The reading obtained is 15.2 cm. If the student's measurement contains a random error of ยฑ0.2 cm, what is the absolute uncertainty in the measurement?
A.
0.1 cm
B.
0.2 cm
C.
0.3 cm
D.
0.4 cm
Show Answer & Explanation
Correct Answer: B
The absolute uncertainty in the measurement is determined by the precision of the measuring instrument (0.1 cm) combined with the random error (ยฑ0.2 cm). Thus, the total uncertainty is ยฑ0.2 cm, which represents the random error's impact on the measurement.
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Practice All 145 Questions →Measurements and Errors โ A-Levels A-Level Physics Practice Questions Online
This page contains 145 practice MCQs for the chapter Measurements and Errors in A-Levels A-Level Physics. The questions are organized by difficulty โ 49 easy, 72 medium, 24 hard โ so you can choose the right level for your preparation.
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