How are clouds formed?
Clouds are formed when air contains as much water vapour as it can hold. This is called the saturation point and it can be reached in two ways. First, moisture accumulates until it reaches the maximum amount the volume of air can hold. The other method reduces the temperature of the moisture filled air, which in turn lowers the amount of moisture it can contain. Saturation, therefore, is reached through evaporation and condensation, respectively. When the saturation occurs, moisture becomes visible water droplets in the form of fog and clouds.
Popular Questions of Class 9 Science
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Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 40 km h-1. What is the average speed for Abdul’s trip?
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An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.
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A driver of a car travelling at 52 km h-1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h-1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?
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Fig 8.11 shows the distance-time graph of three objects A,B and C. Study the graph and answer the following questions:
Fig. 8.11
(a) Which of the three is travelling the fastest?
(b) Are all three ever at the same point on the road?
(c) How far has C travelled when B passes A?
(d) How far has B travelled by the time it passes C? - Q:-
Two objects, each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The velocity of each object is 2.5 m s-1 before the collision during which they stick together. What will be the velocity of the combined object after collision?
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Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
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Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m s-1 and 1 m s-1, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m s-1. Determine the velocity of the second object.
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How do poriferan animals differ from coelenterate animals?
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The speed-time graph for a car is shown is Fig. 8.12.
Fig. 8.12
(a) Find how far does the car travel in the first 4 seconds. Shade the area on the graph that represents the distance travelled by the car during the period.
(b) Which part of the graph represents uniform motion of the car? - Q:-
How are sol, solution and suspension different from each other?
Recently Viewed Questions of Class 9 Science
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What is the role of epidermis in plants?
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Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.
Prokaryotic Cell Eukaryotic Cell 1. Size : generally small (1-10 μm)
1 μm = 10-6 m1. Size generally large (5-100 μm) 2. Nuclear region: ________________
and known as _________________2. Nuclear region: well defined
andsurrounded by a nuclear
membrane3. Chromosome: single
3. More than one chromosome 4. Membrane-bound cell organelles absent 4. _______________________
_______________________ - Q:-
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Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 40 km h-1. What is the average speed for Abdul’s trip?
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Diagrammatically show the difference between the three types of muscle fibres.
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