A piece of iron is heated till it becomes red-hot. It then becomes soft and is beaten to a desired shape. What kind of changes are observed in this process– reversible or irreversible?
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When a carpet is beaten with a stick, dust comes out of it. Explain.
Inertia of an object tends to resist any change in its state of rest or state of motion. When a carpet is beaten with a stick, then the carpet comes...
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Suppose a ball of mass m is thrown vertically upward with an initial speed v, its speed decreases continuously till it becomes zero.
Law of conservation of momentum is applicable to isolated system (no external force is applied). In this case, the change in velocity is due to the gravitational force of earth.
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Which of the following can be beaten into thin sheets? a. Zinc b. Phosphorus c. Sulphur d. Oxygen
Zinc can be beaten into thin sheets.
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In monohybrid cross of red and white flower, Mendel got only red flower. On setting the F1 plants having red flower
On crossing red and white flower only red colour flower appeared in the F1 generation. But the white colour flower again appear in the F2 generation which is raised out...
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A solar water heater cannot be used to get hot water on (a) a sunny day (b) a cloudy day (c) a hot day (d) a windy day
(b) A cloudy day
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A piece of charcoal and a piece of shining steel of the same area are kept for a long time in an open lawn in bright sun.
The correct answer is (c) (d) (c) If both are picked up by bare hands, the steel will be felt hotter than the charcoal. (d) If the two are picked up from...
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Electromagnets are made of soft iron because soft iron has (a) high retentivity and high coercive force
(d) low retentivity and low coercive force.
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‘A’ can complete a piece of work in 12 days. ‘A’ and ‘B’ together can complete the same piece of work in 8 days.
(c) Number of days = 12x8/12-8 = 24 days
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Have you ever burnt your tongue when you ate or drank something that was too hot? How do you cool some food when it is too hot?
Yes, I had once burnt my tongue on drinking very hot tea. When some food is very hot, I cool it by blowing on it, by keeping it in a...
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Assertion (A) : A piece of copper and a piece of glass are heated to the same temperature. When touched,
(b) Both statement 1 and statement 2 are correct. On heating up to same temperature copper piece is found hotter than in comparison to glass piece because copper being a...
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