The pH of rainwater is 7.
The SI unit of charge is volt.
|Column I||Column II||Column III|
|1||Dispersion||Long-sightedness||Twinkling of stars|
|2||Refraction||Splitting of white light into component colours||Convex lens|
|3||Hypermetropia||Change in the direction of the ray of light due to change in medium||Spectrum of seven colours|
The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.
- Calculate the average atomic mass of elements A and C.
- Compare the average atomic mass with atomic mass of B.
- What could the elements A, B and C be?
When the substance ‘A’ is added to a solution of BaSO4, a yellow precipitate is formed.
- What do you think substance A is likely to be?
- Name the precipitate.
- Which type of reaction is this?
A person has sour taste in the mouth and a burning sensation of the stomach.
- What is he suffering from?
- Why does it happen?
- What substance is used as a remedy?
What is myopia? Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.