A LEVEL PHYSICS
PRACTICE EXAM
Question 1: A micrometer screw gauge has a zero error of +0.03 mm. It reads 2.48 mm when measuring a wire. What is the corrected diameter of the wire?
Choices:
1) 2.45 mm 2) 2.48 mm 3) 2.51 mm 4) 2.54 mm
Correct Answer: 2.45 mm
Explanation: A positive zero error means the instrument reads too high. Corrected reading = 2.48 mm - 0.03 mm = 2.45 mm.Page 1
Question 2: Which quantity has the same base SI units as impulse?
Choices:
1) Force 2) Momentum 3) Power 4) Pressure
Correct Answer: Momentum
Explanation: Impulse equals force multiplied by time, so its units are N s = kg m s^-1, the same as momentum.Question 3: A student records a length as 0.03640 m. How many signi�cant �gures are shown?
Choices:
1) 2 2) 3 3) 4 4) 5
Correct Answer: 4
Explanation: Leading zeros are not signi�cant. The digits 3, 6, 4 and the �nal zero after the decimal point are signi�cant, giving 4 signi�cant �gures.Page 2
Question 4: The percentage uncertainty in a resistance R is 2%. What is the
percentage uncertainty in R^2?
Choices:
1) 1% 2) 2% 3) 4% 4) 8%
Correct Answer: 4%
Explanation: For a power, the percentage uncertainty is multiplied by the power. For R^2 it is 2 x
2% = 4%.
Question 5: A ball is thrown vertically upwards with an initial speed of 18 m s^-1.Taking g as 9.8 m s^-2, what is its maximum height above the release point?
Choices:
1) 16.5 m 2) 18.4 m 3) 33.1 m 4) 36.7 m
Correct Answer: 16.5 m
Explanation: At maximum height v = 0. Using v^2 = u^2 + 2as gives 0 = 18^2 - 2(9.8)s, so s = .6 = 16.5 m.Page 3