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The plane in which the earth revolves around the sun is called the equatorial plane of earth. (True or False)

Answer: The plane in which the earth revolves around the sun is called the equatorial plane of earth - False Earth revolves around the sun in... View Article

The planet nearest to us is Jupiter. (True or False)

Answer: The planet nearest to us is Jupiter - False Mercury is the nearest planet to the Earth. Mercury is the smallest planet in the solar... View Article

The planet Venus appears in the eastern sky before sunrise. (True or False)

Answer: The planet Venus appears in the eastern sky before sunrise - True Venus appears either in the eastern sky before sunrise or in the... View Article

The planets do not emit light of their own. (True or False)

Answer: The planets do not emit light of their own - True Stars have their own light and twinkle in the night, but a planet does not have their... View Article

The planets keep changing their position with respect to stars. (True or False)

Answer: The planets keep changing their position with respect to stars - True Planets are celestial bodies that do not emit heat or light of... View Article

The plates of the outermost layer of the earth are always in continuous motion. (True & False)

Answer: True The earth’s lithosphere is composed of seven or eight major plates and many minor plates. The lithosphere is a rigid outermost... View Article

The process of depositing a layer of any desired metal on another material by means of electricity is called _________.

Answer: The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating.... View Article

The process of electric discharge cannot occur between clouds and the earth. (True & False)

Answer: False The process of electric discharge occurs between clouds and the earth. Lightning is easily explained as a spark that occurs on a... View Article

The strips of an electroscope diverge when a charged body is brought in contact with the metal clip. Now the clip is touched gently by our hand. What will happen to the strips? Explain.

Answer: When we touch strips of electroscope with our hand, the charge in the strips is discharged through our hand, and the strips return to... View Article

The town hall building is situated close to Boojho’s house. There is a clock on the top of the town hall building which rings the bell every hour. Boojho has noticed that the sound of the clock appears to be much clearer at night. Explain.

Answer: To travel, sound required a medium. Sound cannot travel in a vacuum because there is no medium to transmit sound waves. So it requires a... View Article

The two regions of the earth with extreme climatic conditions are _ and .

Answer: The two regions of the earth with extreme climatic conditions are the polar region and the tropical region. The polar regions represent... View Article

The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.

Answer: In a thunderstorm, we should not bring an umbrella because thunderstorms are usually accompanied by lightning. During lightning,... View Article

There is a mistake in each of the following ray diagrams given as Fig. a, b, and c. Make the necessary correction (s).

Answer: The angle of incidence is equal to the reflected angle through the law of reflection. The angle of incidence and the angle of... View Article

Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator.

Answer: The following steps are taken to test the given liquids: Put a drop of provided liquid on the turmeric indicator. The solution that... View Article

To sharpen the blade of a knife by rubbing it against a surface, which of the following will be most suitable? (a) stone (b) plastic block (c) wooden block (d) glass block

Answer: (a) stone The stone will be more suitable since it will provide a greater reaction and hence a higher friction force, allowing the blade... View Article

Tremors on the earth can also be caused by the eruption of a volcano. (True & False)

Answer: True A volcano is a landform, a mountain, where molten rocks erupt through the surface of the planet. The volcano mountain opens... View Article

Two astronauts are floating close to each other in space. Can they talk to each other without using any special device? Give reasons.

Answer: In space, there will be no medium for sound waves to travel through, only vacuum. Because sound cannot travel through vacuum, it must... View Article

Two blocks of iron of different masses are kept on a cemented floor as shown in Fig.12.2. Which one of them would require a larger force to move it from the rest position?

Answer: A larger force will be required to move the heavier block. Because the force of friction increases as the mass of the object... View Article

Two boys are riding their bicycles on the same concrete road. One has new tyres on his bicycle while the other has tyres that are old and used. Which of them is more likely to skid while moving through a patch of the road which has lubricating oil spilt over it?

Answer: The boy with the old and worn tyres is more likely to slip since the tyres will have less friction force, which will be insufficient to... View Article

Two charged objects are brought close to each other. Choose the most appropriate statement from the following options: (a) they may attract (b) they may repel (c) they may attract or repel depending on the type of charges they carry (d) there will be no effect

Answer: (c) they may attract or repel depending on the type of charges they carry If the charges are like, they repel each other, and if they are... View Article

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