A Level Physics Practice Exam

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