Q1. Which of the following is NOT a state of matter?
a) Solid
b) Liquid
c) Gas
d) Plasma
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Correct Answer: d) Plasma
Explanation: Plasma is often considered the fourth state of matter, distinct from solids, liquids, and gases. It is a state where matter is ionized and consists of free-moving ions and electrons. Plasma is commonly found in stars, lightning, and certain man-made devices like neon lights and plasma TVs.
Q2. The process of a solid turning directly into a gas without passing through the liquid state is called:
a) Sublimation
b) Vaporization
c) Condensation
d) Evaporation
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Correct Answer: a) Sublimation
Explanation: Sublimation is the transition of a substance from the solid phase directly to the gas phase without passing through the intermediate liquid phase. Examples include dry ice (solid carbon dioxide) turning into carbon dioxide gas and mothballs gradually vaporizing.
Q3. What is the boiling point of water in Celsius?
a) 0°C
b) 100°C
c) 273°C
d) 212°C
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Correct Answer: b) 100°C
Explanation: Water boils at 100 degrees Celsius under standard atmospheric pressure. This temperature is a defining point of the Celsius temperature scale, making it a crucial reference point in various scientific contexts and everyday applications.
Q4. Which of the following is NOT a characteristic of a gas?
a) Definite volume
b) Ability to expand to fill its container
c) Low density
d) Compressibility
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Correct Answer: a) Definite volume
Explanation: Unlike solids and liquids, gases do not have a definite volume. Instead, they take the shape and volume of their container, as they can expand or compress freely depending on external conditions.
Q5. What is the process called when a gas changes into a liquid?
a) Condensation
b) Evaporation
c) Sublimation
d) Vaporization
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Correct Answer: a) Condensation
Explanation: Condensation is the process by which a gas changes into a liquid when it loses heat energy. It is the opposite of vaporization. Examples of condensation include the formation of dew on grass in the morning or the creation of clouds in the atmosphere.
Q6. Which of the following is NOT a property of solids?
a) Definite shape
b) Definite volume
c) Ability to flow
d) Particles closely packed
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Correct Answer: c) Ability to flow
Explanation: Solids have a definite shape and volume because their particles are closely packed and arranged in a fixed pattern. Unlike liquids, solids do not flow freely, maintaining their shape under normal conditions.
Q7. At what temperature do Celsius and Fahrenheit scales have the same numerical value?
a) -40°C
b) 0°C
c) 100°C
d) 212°C
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Correct Answer: a) -40°C
Explanation: -40 degrees Celsius is equivalent to -40 degrees Fahrenheit. This unique temperature serves as a point of convergence between the Celsius and Fahrenheit temperature scales, making it a notable reference point in thermometry.
Q8. Which of the following is NOT a physical state of matter?
a) Bose-Einstein condensate
b) Liquid crystal
c) Superfluid
d) Photonic crystal
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Correct Answer: d) Photonic crystal
Explanation: Photonic crystal is not a physical state of matter; rather, it is a man-made nanostructured material used in photonics, specifically designed to control and manipulate the flow of light.
Q9. The process of a liquid turning into a gas at temperatures below its boiling point is called:
a) Sublimation
b) Vaporization
c) Condensation
d) Evaporation
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Correct Answer: d) Evaporation
Explanation: Evaporation is the process by which a liquid turns into a gas at temperatures below its boiling point. It occurs at the surface of the liquid, where molecules gain enough kinetic energy to escape into the surrounding space as vapor.
Q10. What is the freezing point of water in Fahrenheit?
a) 0°F
b) 32°F
c) 100°F
d) 212°F
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Correct Answer: b) 32°F
Explanation: Water freezes at 32 degrees Fahrenheit under standard atmospheric pressure. This temperature serves as a reference point in the Fahrenheit temperature scale, marking the transition of water from a liquid to a solid state.