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प्रश्न
State whether the following statement is true or false. If false write the correct statement.
Desirable changes are meaningful, while undesirable changes are unfavourable.
पर्याय
True
False
उत्तर
True
APPEARS IN
संबंधित प्रश्न
Tick (√) the correct alternative from the choice given for the following statement.
When we add water to the following substances, which one will show a chemical change?
Name the temperature at which :
- a liquid changes into a gas.
- a solid changes into a liquid.
What is the common name of solid carbon dioxide ?
Fill in the following blank with suitable words :
The state of matter called ........................ makes a fluorescent tube (or neon sign bulb) to glow.
Why does the temperature of a substance remain constant during the change of state ?
Define the following term Melting.
Define the term 'latent heat of vaporisation' of a liquid. What is the value of the latent heat of vaporisation of water ?
Define the following terms: Boiling point
Fill in the blanks:
The molecules are at a greater distance in ______ compared to liquids.
Fill in the blanks:
Water boils at ______.
Explain the term melting
Explain the term boiling point
Who am I?
I have no shape whatsoever!
Photosynthesis is a natural process by which green plants manufacture food in the presence of sunlight.
Are any new products formed during the above process.
Fill in the blanks with the correct words of the statement given below:
During sublimation, a solid on heating turns directly into _________ and on cooling back to __________.
With reference to the liquid state of matter – answer the following
The heat energy supplied to the liquid is absorbed by its molecule & stored as which form of energy.
Give the reason for the following
Solids cannot be compressed, but gases are highly compressible.
Give the reason for the following:
The kinetic energy of molecules of gases is very large & of solids, the least.
Complete the blank with reference to interconversion of matter on the basis of kinetic theory-with the word ‘increase’, ‘decreases’, ‘gain’, ‘lose’, or ‘overcome’ in the following case.
During liquefaction, the particles ________ energy.
Prepare a model to demonstrate movement of particles in solids, liquids and gases.
For making this model you will need
- A transparent jar
- A big rubber balloon or piece of stretchable rubber sheet
- A string
- Few chickpeas or black gram or dry green peas.
How to make?
- Put the seeds in the jar.
- Sew the string to the centre of the rubber sheet and put some tape to keep it tied securely.
- Stretch and tie the rubber sheet on the mouth of the jar.
- Your model is ready. Now run your fingers up and down the string by first tugging at it slowly and then rapidly.
