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Matter In Our Surroundings
A coolie is walking on a railway platform with 20 kg load on his head. What is the amount of work done by him? Justify your answer.
Work done is zero because the load does not get displaced from the coolie's head. Hence, the work done is zero.
Therefore, using the formula,
W = Fs cos 90° = 0.
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For any substance, why does the temperature remain constant during the change of state ?
Suggest a method to liquify atmospheric gases.
Convert the following temperatures to Kelvin scale.
35°C
Give reason for the following observations.
Naphthalene balls disappear with time without leaving any solid.
Give reason for the following observations.
We can get the smell of perfume sitting several metres away.
What is the physical state of water at
a) 25°C
b)00C
c)1000C
What is the physical state of water at
0°C
What is the physical state of water at
100°C
Give two reasons to justify
Water at room temperature is a liquid.
Give two reasons to justify
An iron almirah is a solid at room temperature.
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