Matter in Our Surroundings Class 9 MCQ With Answers Set-3
Q31. What is sublimation?
A. The process of changing from a solid state directly to a gaseous state without changing into a liquid state.
B. The process of changing from a liquid state directly to a solid state without changing into the gaseous state.
C. The process of changing from a gaseous state directly to a solid state without changing into a liquid state.
D. The process of changing from a liquid state directly to a gaseous state without changing into a solid state.
Answer – A. The process of changing from a solid state directly to a gaseous state without changing into a liquid state.
Explanation-
Q32. Which of the following substances sublimates?
A. Ice
B. Water
C. Carbon dioxide
D. All of the above
Answer – C. Carbon dioxide
Explanation-Carbon dioxide sublimates, meaning it goes directly from a solid state to a gaseous state without changing into a liquid state. Ice and water do not sublime.
Q33. Which of the following is NOT a factor that affects the state of matter?
A. Pressure
B. Temperature
C. Force
D. Volume
Answer – C. Force
Explanation-Force is not a factor that affects the state of matter. Pressure, temperature, and volume are all factors that affect the state of matter.
Q34. What is the process of changing directly from a solid state to a gaseous state called?
A. Sublimation
B. Deposition
C. Liquefaction
D. Solidification
Answer –A. Sublimation
Explanation-Sublimation is the process of changing directly from a solid state to a gaseous state without changing into a liquid state.
Q35. What is the process of changing directly from a gaseous state to a solid state called?
A. Sublimation
B. Deposition
C. Liquefaction
D. Solidification
Answer – B. Deposition
Explanation-Deposition is the process of changing directly from a gaseous state to a solid state without changing into a liquid state.
Q36. Which of the following substances sublimates?
A. Water
B. Carbon dioxide
C. Mercury
D. None of the above
Answer – B. Carbon dioxide
Explanation-Carbon dioxide sublimates, meaning it goes directly from a solid state to a gaseous state without changing into a liquid state. Water, mercury, and most other substances do not sublime.
Q37. How can gases be liquefied?
A. By increasing the pressure
B. By decreasing the temperature
C. Both A. and (B)
D. None of the above
Answer – C. Both A. and B
Explanation-The liquefaction of gases can be achieved by increasing the pressure, decreasing the temperature, or both.
Q38. Which of the following is NOT a factor that affects atmospheric pressure?
A. Altitude
B. Temperature
C. Gravity
D. Air density
Answer –C. Gravity
Explanation-Gravity is not a direct factor that affects atmospheric pressure. Air pressure is caused by the weight of the air molecules above us. Gravity does affect the air density, which indirectly affects atmospheric pressure.
Q39. What is the atmospheric pressure at sea level?
A. 1 atmosphere
B. 101.325 kPa
C. 760 mmHg
D. All of the above
Answer – D. All of the above
Explanation-1 atmosphere, 101.325 kPa, and 760 mmHg are all equivalent units of atmospheric pressure at sea level.
Q40. How does atmospheric pressure change with altitude?
A. It increases with altitude.
B. It decreases with altitude.
C. It remains constant with altitude.
D. None of the above
Answer – B. It decreases with altitude.
Explanation-Atmospheric pressure decreases with altitude because there are fewer air molecules above us at higher altitudes.
