Questions
Raj's car is parked outside the house for two days during winter. After two days, he saw that the windscreen of the car has becomes hazy. Which of the following can be the reason for the haziness of the windscreen?
- Presence of dust particles
- Presence of fog
- Presence of smoke particles
- All of the above
What is/are the use(s) of air for plants?
- The dispersal of seeds
- The dispersal of pollen of flowers
- Air is a source of Nitrogen for them
- Both (1) and (2)
The policeman regulating traffic at a crowded crossing often wears a mask. What is/are the reason(s)?
(a) To release oxygen from the mask
(b) To prevent himself from the dust and smoke
(c) So that he doesn't have to hold a handkerchief when he sneezes as his hands are preoccupied directing the traffic
- Only (a)
- Only (b)
- Only (b) and (c)
- Only (c)
Why is one advised to throw a blanket over a burning object during an incident of fire?
- To cut off the contact between oxygen and the burning object
- To cut off the contact between nitrogen and the burning object
- To cut off the contact between noble gases and the burning object
- To cut off the contact between water vapours and the burning object
Which of the following statements is/are true?
(a) Air contains water vapours.
(b) When air comes in contact with a hot surface, it condenses.
(c) When water vapour from the air condenses, the drops of water appear on the surface of an object.
- Only (a)
- Only (b) and (c)
- Only (a) and (c)
- Only (b)
Sonam went on the roof of her house with a firki and noticed that her firki starts rotating. What is/are the reason(s)?
(a) Beacause the side of the firki facing the sun gets hotter and hence becomes lighter which causes it to rotate
(b) Because the force of air was rotating the firki
(c) Because the structure of a firki is such that it is not alligned with its central rotational axis which causes it to keep on rotating
- Only (a) and (b)
- Only (b)
- Only (c)
- Only (a) and (c)
Plants and animals depend on each other for exchange of _______ and ______ from air.
- oxygen; carbon dioxide
- oxygen; nitrogen
- carbon dioxide; water
- carbon dioxide; nitrogen
Which of the following statements is/are true?
- Animals use air for respiration.
- Plants use air to prepare their food.
- Air helps in power generation by wind turbines.
- All of the above
If there is no oxygen in the room and Rani throws a burning paper inside that room, what will happen to the burning paper?
- Paper will start burning rapidly.
- Paper will start burning slowly.
- Paper will not burn anymore.
- Paper will produce oxygen on burning.
Which of the following statements is true?
- Air is transparent.
- Air does not occupy space.
- Air is not so essential for life on earth.
- Air is not present in the soil.
Which of the following statements is/are true?
- Air helps in the movements of sailing yachts.
- Air helps in the movements of a kite.
- Air helps in the movements of aeroplanes and gliders.
- All of the above
Why does all the oxygen in the atmosphere not get used up though a large number of organisms are consuming it?
- Oxygen is produced using oxygen cylinders.
- Oxygen is replenished in the air by the plants during photosynthesis.
- Oxygen is released in the atmosphere from the oceans by aquatic animals.
- Oxygen is released in the atmosphere by respiration of animals.
Raju has a beaker filled with water. He started heating the water with a burner. Before the water began to boil, he saw tiny bubbles in the water beaker. What do these bubbles show?
- Water is evaporating
- Air is dissolved in water
- Bubbles of hydrogen are coming out
- Both (1) and (3)
The major part of air which does not support burning is _________.
- carbon dioxide
- oxygen
- nitrogen
- hydrogen