You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?
A daily weather forecast is the work of people working for the weather department to collect data on the elements of weather such as maximum and minimum temperatures, maximum and minimum humidity, rainfall, wind speed, etc. Weather satellites are present to take photographs of clouds from space. The maximum and minimum temperature of a day is measured by a thermometer known as the maximum−minimum thermometer. Rainfall is measured by an instrument known as the rain gauge. Wind speed is measured by anemometers. There are various instruments used to measure humidity.
Popular Questions of Class Science
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Convert into mole.
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide. - Q:-
Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?
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Why is the atmosphere essential for life?
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Why is the weight of an object on the moon 1/6th its weight on the earth?
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What happens to the force between two objects, if
(i) the mass of one object is doubled?
(ii) the distance between the objects is doubled and tripled?
(iii) the masses of both objects are doubled? - Q:-
Why are we normally advised to take bland and nourishing food when we are sick?
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You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?
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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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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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Explain the working and application of a sonar.
Recently Viewed Questions of Class Science
- Q:-
Why is the weight of an object on the moon 1/6th its weight on the earth?
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A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m.
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How are sol, solution and suspension different from each other?
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An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s-1?
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What do you mean by buoyancy?
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Compare the use of manure and fertilizers in maintaining soil fertility.
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What does the odometer of an automobile measure?
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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:-
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:-
Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?
- NCERT Chapter