Page 20 - Q & A STPM 2022 Physics

Physics Semester 1 STPM Chapter 1 Physical Quantities and Units
∆A = ∆L + ∆W = 0.05 + 0.05
A L W 12.8 23.75 Common Error

∆A = 0.006012(304) = 1.83 Uncertainty is in one significant
∴ A = 304 ± 2 cm 2 figure.
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Question 3

A student measured the length of a pendulum as 17.5 ± 0.05 cm. The Semester
fractional error in the measurement of the period T is 0.03. The student uses
the formula T = 2π l to calculate the value of g. Find the fractional error in
g 1
the calculated value of g.
A 0.03
B 0.04
C 0.05
D 0.06

Answer : D

T = 2π l
g
2
T = 4π 2 l
g
4π l
2
g =
T 2
∆g ∆l 2∆T
g = l + T

= 0.05 + 2(0.03)
17.5
= 0.063

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01 STPM Q&A PHY T1.indd 11 17/02/2022 10:03 AM