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प्रश्न
You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster?
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उत्तर
The process of drying the shirt can be made faster in the following ways:
- Spread the shirt to increase the surface area which will increase the rate of evaporation.
- Put it in the sun to increase the temperature to increase the rate of evaporation.
- Keep it under the fan to increase the wind speed which increases the rate of evaporation.
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संबंधित प्रश्न
The smallest unit of matter that exists freely in nature is called ...........
Name the terms for the change of vapour into a liquid.
Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into
(i) osmosis, and (ii) diffusion :
- swelling up of a raisin on keeping in water
- spreading of virus on sneezing
- earthworm dying on coming in contact with common salt
- shrinking of grapes kept in thick sugar syrup
- preserving of pickles in salt
- spreading of smell of cake being baked in the kitchen
- aquatic animals using oxygen dissolved in water during respiration
During respiration, glucose and oxygen enter our body cells and waste products carbon dioxide and water leave the body cells by the process of :
What elements do the following compounds contain ?
Sugar, Common salt
What are the three groups into which all the elements can be divided ? Name two elements belonging to each group.
You are given two liquids, one a solution and the other a compound. How will you distinguish the solution from the compound ?
Iron powder and sulphur powder were mixed together and divided into two parts A and B. When part A was heated strongly over a burner, then a substance C was formed. The part B was, however, not heated at all. When dilute hydrochloric acid was added to substance C, then gas D was evolved and when dilute hydrochloric acid was added to part B then gas E was evolved.
- What type of substance is B ?
- What type of substance is C ?
- Name the gas (i) D, and (ii) E ?
- State one characteristic property of gas D.
- Write one test to identify gas E.
There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
- What could the group of materials P be ?
- Name the substances Q. Give two examples of such substances.
- Name the substances R. Write two examples of such substances.
- Name the substances S. Give two examples of such substances.
- Out of Q, R and S, which substances are malleable and ductile ?
Out of a colloid, solution and a suspension :
which one has the largest particles ?
Explain what happens when a beam of light is passed through a colloidal solution.
What do you understand by the statement " the solubility of copper sulphate in water at 20°C is 20.7 g" ?
One of the following represents the solution of solid in a solid. This one is :
Name the process which is used in milk dairies to separate cream from milk.
Explain the meaning of the term ‘matter’.
A standard sheet of paper is about ______ of atoms thick
Rusting of an article made up of iron is called
The most reactive metal is ______.
Define the term matter.
