Matter in Our Surroundings Class 9 MCQ With Answers Set-5
Q41. What is the barometric pressure?
A. The pressure of the air in the atmosphere
B. The pressure of the air inside a barometer
C. Both A. and B.
D. None of the above
Answer – C. Both A. and (B)
Explanation-The barometric pressure is the pressure of the air in the atmosphere, as measured by a barometer.
Q42. What is the relationship between atmospheric pressure and weather?
A. Atmospheric pressure can affect weather conditions such as wind speed and precipitation.
B. Weather conditions can affect atmospheric pressure.
C. Both A. and B.
D. None of the above
Answer – C. Both A. and (B)
Explanation-Atmospheric pressure and weather conditions are interrelated. For example, low atmospheric pressure is often associated with stormy weather, while high atmospheric pressure is often associated with clear skies.
Q43. Which of the following is NOT a factor that affects the rate of evaporation?
A. Temperature
B. Surface area
C. Wind speed
D. Humidity
Answer – D. Humidity
Explanation-Humidity is a measure of the amount of water vapor in the air. Higher humidity means that the air is already saturated with water vapor, which makes it more difficult for liquid water to evaporate.
Q44. Which of the following is an example of evaporation?
A. Ice melting in a glass of water
B. Water boiling in a pot
C. A puddle drying up on a sunny day
D. All of the above
Answer – D. All of the above
Explanation-All of the above are examples of evaporation. Ice melting in a glass of water is an example of sublimation, which is a different process.
Q45. Why does water evaporate even when it is not boiling?
A. Because particles of matter are always moving and have different amounts of kinetic energy.
B. Because the air is always saturated with water vapor.
C. Because of the force of gravity.
D. None of the above
Answer –A. Because particles of matter are always moving and have different amounts of kinetic energy.
Explanation-At any given temperature, some particles of a liquid will have enough kinetic energy to break free from the forces of attraction of the other particles and evaporate. This is why water can evaporate even when it is not boiling.
Q46. Which of the following will evaporate the fastest?
A. A puddle on a hot, sunny day
B. A puddle on a cold, cloudy day
C. A puddle in a humid environment
D. A puddle in a dry environment
Answer – A. A puddle on a hot, sunny day
Explanation-Evaporation is faster at higher temperatures and in drier environments.
Q47. Which of the following will NOT increase the rate of evaporation?
A. Increasing the surface area
B. Increasing the temperature
C. Increasing the humidity
D. Increasing the wind speed
Answer – C. Increasing the humidity
Explanation-Increasing the humidity will actually decrease the rate of evaporation. This is because the air is already saturated with water vapor, making it more difficult for liquid water to evaporate.
Q48. Why do clothes dry faster on a windy day?
A. Because the wind increases the surface area of the clothes.
B. Because the wind increases the temperature of the clothes.
C. Because the wind decreases the humidity around the clothes.
D. All of the above
Answer –C. Because the wind decreases the humidity around the clothes.
Explanation-The wind decreases the humidity around the clothes by blowing away the water vapor that is evaporating. This makes it easier for more water to evaporate, and the clothes dry faster.
Q49. Which of the following substances will evaporate the fastest?
A. A puddle of water on a hot, sunny day
B. A puddle of water on a cold, cloudy day
C. A puddle of water in a humid environment
D. A puddle of water in a dry environment
Answer – A. A puddle of water on a hot, sunny day
Explanation-The rate of evaporation is faster at higher temperatures and in drier environments.
Q50. Why do we spread out our clothes to dry them?
A. To increase the surface area of the clothes.
B. To increase the temperature of the clothes.
C. To decrease the humidity around the clothes.
D. All of the above
Answer –A. To increase the surface area of the clothes.
Explanation-Increasing the surface area of the clothes increases the rate of evaporation, helping them to dry faster.
