Thermal Expansion Practice Questions
KCSE (Kenya) · KCSE Physics · 150 free MCQs with instant results and detailed explanations.
150
Total
51
Easy
70
Medium
29
Hard
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Sample Questions from Thermal Expansion
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Q1
Easy
What happens to the volume of a gas when it is heated at constant pressure?
A.
It decreases.
B.
It remains the same.
C.
It increases.
D.
It evaporates.
Show Answer & Explanation
Correct Answer: C
According to Charles's Law, when a gas is heated at constant pressure, its volume increases. This is because the kinetic energy of the gas molecules increases, causing them to move apart and occupy more space.
Q2
Easy
When a metal rod is heated, what type of expansion does it undergo?
A.
Lateral expansion.
B.
Linear expansion.
C.
Volume expansion.
D.
No expansion.
Show Answer & Explanation
Correct Answer: B
When a metal rod is heated, it undergoes linear expansion. This means that its length increases as the temperature increases, due to the increase in kinetic energy of its atoms.
Q3
Easy
A glass jar tightly holds a metal lid. What method can you apply to easily open the jar?
A.
Cooling the jar.
B.
Heating the lid.
C.
Cooling the lid.
D.
Applying pressure on the lid.
Show Answer & Explanation
Correct Answer: B
Heating the lid causes it to expand more than the glass jar due to thermal expansion. This makes it easier to unscrew the lid as the increased size allows for better clearance and reduces the grip.
Q4
Medium
What happens to the density of a substance when it is heated, assuming it expands uniformly?
A.
Density increases
B.
Density decreases
C.
Density remains constant
D.
Density first increases, then decreases
Show Answer & Explanation
Correct Answer: B
When a substance is heated, it expands, occupying a larger volume. Since density is mass per unit volume, an increase in volume while mass remains constant results in a decrease in density.
Q5
Medium
Which of the following materials typically has the highest coefficient of thermal expansion?
A.
Steel
B.
Gold
C.
Glass
D.
Wood
Show Answer & Explanation
Correct Answer: B
Gold has a higher coefficient of thermal expansion compared to steel, glass, and wood, meaning it expands more for a given temperature change. This property is crucial in applications involving precision.
Q6
Medium
When a liquid is heated, which of the following effects is observed?
A.
It contracts and becomes denser
B.
It expands and becomes less dense
C.
It remains unchanged in volume
D.
It vaporizes immediately
Show Answer & Explanation
Correct Answer: B
When a liquid is heated, it expands, which increases its volume. As a result, its density decreases because density is mass per unit volume. This phenomenon is observed in most liquids.
Q7
Medium
What is the primary reason why bridges are designed with expansion joints?
A.
To allow for aesthetic designs
B.
To accommodate thermal expansion
C.
To reduce the weight of the bridge
D.
To prevent rusting
Show Answer & Explanation
Correct Answer: B
Expansion joints in bridges are designed to allow for thermal expansion and contraction of the materials due to temperature changes. This prevents structural damage that could occur if the materials were fixed in place.
Q8
Hard
A metal rod of length 2.0 m at 20°C is heated to 80°C. Given that the coefficient of linear expansion for the metal is 1.2 x 10^-5 /°C, what will be the increase in length of the rod?
A.
0.144 m
B.
0.144 cm
C.
0.24 m
D.
0.24 cm
Show Answer & Explanation
Correct Answer: B
The increase in length of the rod can be calculated using the formula ΔL = L0 * α * ΔT, where L0 is the original length, α is the coefficient of linear expansion, and ΔT is the change in temperature. Here, ΔL = 2.0 m * 1.2 x 10^-5 /°C * (80°C - 20°C) = 0.144 cm.
Q9
Hard
A glass container filled with water is placed in a freezer. As the water cools from 0°C to -5°C, which of the following statements is true regarding the volume of the water?
A.
The volume decreases uniformly.
B.
The volume remains constant.
C.
The volume decreases then increases.
D.
The volume increases uniformly.
Show Answer & Explanation
Correct Answer: C
Water behaves unusually; it actually expands when it freezes at 0°C. As the temperature drops from 0°C to -5°C, the volume decreases until it reaches 0°C and then begins to increase as it approaches freezing, resulting in an overall decrease in volume before expansion.
Q10
Hard
A metal rod of length 2 m at 20°C expands to 2.002 m when heated to a temperature of 100°C. What is the coefficient of linear expansion for the metal?
A.
1.0 x 10^-5 /°C
B.
1.0 x 10^-6 /°C
C.
1.5 x 10^-5 /°C
D.
2.0 x 10^-5 /°C
Show Answer & Explanation
Correct Answer: A
The coefficient of linear expansion is calculated using the formula α = ΔL / (L0 * ΔT). Here, ΔL = 0.002 m, L0 = 2 m, and ΔT = 80°C. Plugging in the values gives α = 0.002 / (2 * 80) = 1.0 x 10^-5 /°C.
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Thermal Expansion — KCSE (Kenya) KCSE Physics Practice Questions Online
This page contains 150 practice MCQs for the chapter Thermal Expansion in KCSE (Kenya) KCSE Physics. The questions are organized by difficulty — 51 easy, 70 medium, 29 hard — so you can choose the right level for your preparation.
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