A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.
No work has been done because the bundle of hay remains stationary. That is, the displacement is zero. So, the work done is also zero.
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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