You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?
The weighing machine reads slightly less than the actual value. This is because of the upthrust of air acting on our body. Hence, the body gets pushed slightly upwards, causing the weighing machine to show a reading less than the actual value.
Popular Questions of Class Science
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Convert into mole.
(a) 12 g of oxygen gas
(b) 20 g of water
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Why is the atmosphere essential for life?
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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?
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Why are we normally advised to take bland and nourishing food when we are sick?
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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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In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?
• if you get jaundice,
• if you get lice,
• if you get acne.Why?
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Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt. - Q:-
What are the immunisation programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?
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A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity.
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Under which of the following conditions are you most likely to fall sick?
(a) when you are taking examinations.
(b) when you have travelled by bus and train for two days.
(c) when your friend is suffering from measles.Why?
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A bus decreases its speed from 80 km h-1 to 60 km h-1 in 5 s. Find the acceleration of the bus.
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Write down the formulae of
(i) sodium oxide
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(iii) sodium suphide
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Why is it not possible to see an atom with naked eyes?
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Name the technique to separate
(i) butter from curd,
(ii) salt from sea-water,
(iii) camphor from salt. - Q:-
Convert into mole.
(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide. - Q:-
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(a) saturated solution
(b) pure substance
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A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?
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Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?
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Name the regions in which parenchyma tissue is present.
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