Q1. What happens to the volume of a gas when it is heated?
a) Increases
b) Decreases
c) Remains constant
d) Depends on the type of gas
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Correct Answer: a) Increases
Explanation: When a gas is heated, its particles gain kinetic energy, leading to increased collisions with the container walls, causing the volume to expand.
Q2. Which of the following materials experiences the least thermal expansion?
a) Solid
b) Liquid
c) Gas
d) Depends on the material
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Correct Answer: c) Gas
Explanation: Gases typically experience the least thermal expansion compared to solids and liquids due to their low density and weak intermolecular forces.
Q3. What is the coefficient of linear expansion?
a) A constant value for all materials
b) The change in volume per unit temperature change
c) The change in length per unit temperature change
d) The change in mass per unit temperature change
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Correct Answer: c) The change in length per unit temperature change
Explanation: The coefficient of linear expansion represents the change in length per unit temperature change for a particular material.
Q4. What type of thermal expansion occurs when an object expands in all directions?
a) Linear expansion
b) Area expansion
c) Volume expansion
d) Cubic expansion
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Correct Answer: c) Volume expansion
Explanation: Volume expansion occurs when an object expands in all directions, resulting in an increase in its volume with temperature.
Q5. What happens to the density of a substance when it undergoes thermal expansion?
a) Increases
b) Decreases
c) Remains constant
d) Depends on the substance
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Correct Answer: b) Decreases
Explanation: As a substance undergoes thermal expansion, its volume increases while its mass remains constant, leading to a decrease in density.
Q6. Which property of a material is NOT affected by thermal expansion?
a) Length
b) Area
c) Volume
d) Mass
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Correct Answer: d) Mass
Explanation: Thermal expansion affects the dimensions (length, area, volume) of a material, but not its mass, which remains constant.
Q7. What term describes the phenomenon where a substance contracts upon cooling after being heated and expanded?
a) Contraction
b) Compression
c) Expansion
d) Contraction
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Correct Answer: d) Contraction
Explanation: Contraction is the phenomenon where a substance contracts or shrinks upon cooling after being heated and expanded.
Q8. Which of the following is an example of a practical application of thermal expansion?
a) Manufacturing glassware
b) Constructing bridges
c) Generating electricity
d) All of the above
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Correct Answer: d) All of the above
Explanation: Thermal expansion is used in various practical applications such as manufacturing glassware, constructing bridges with expansion joints, and generating electricity in thermal power plants.
Q9. What happens to the density of water when it freezes?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
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Correct Answer: a) Increases
Explanation: When water freezes, it expands and its density decreases, causing it to become less dense than the surrounding liquid water, which is why ice floats.
Q10. Which of the following materials typically has the highest coefficient of linear expansion?
a) Metal
b) Wood
c) Plastic
d) Glass
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Correct Answer: a) Metal
Explanation: Metals generally have higher coefficients of linear expansion compared to other materials like wood, plastic, and glass, making them more susceptible to thermal expansion.
Q11. What is the coefficient of volume expansion?
a) A constant value for all materials
b) The change in length per unit temperature change
c) The change in area per unit temperature change
d) The change in volume per unit temperature change
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Correct Answer: d) The change in volume per unit temperature change
Explanation: The coefficient of volume expansion represents the change in volume per unit temperature change for a particular material.
Q12. Which of the following materials exhibits the greatest expansion upon heating?
a) Solid
b) Liquid
c) Gas
d) All expand equally
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Correct Answer: c) Gas
Explanation: Gases exhibit the greatest expansion upon heating compared to solids and liquids due to their lower density and weaker intermolecular forces.
Q13. What term describes the process of decreasing temperature leading to a decrease in volume of a gas?
a) Expansion
b) Contraction
c) Compression
d) Expansion and contraction are the same
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Correct Answer: b) Contraction
Explanation: Contraction is the process where a substance reduces in volume due to cooling after being heated and expanded.
Q14. Which factor does NOT influence the degree of thermal expansion in a material?
a) Type of material
b) Initial temperature
c) Length of the material
d) Coefficient of thermal expansion
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Correct Answer: c) Length of the material
Explanation: The degree of thermal expansion in a material is influenced by factors such as the type of material, its initial temperature, and the coefficient of thermal expansion, but not by the length of the material.
Q15. What happens to the density of a substance when it undergoes thermal contraction?
a) Increases
b) Decreases
c) Remains constant
d) Depends on the substance
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Correct Answer: a) Increases
Explanation: When a substance undergoes thermal contraction, its volume decreases while its mass remains constant, leading to an increase in density.