Is Matter Around Us Pure
What is a hearing aid ? Briefly describe its working principle.
A battery operated electronic device used by persons who cannot hear properly is called as hearing aid.
Working of the hearing aid is as follows:
Hearing aid receives sound through a microphone. The microphone converts the sound waves to electrical signals. These electrical signals are amplified by an amplifier. The amplified electrical signals are given to a speaker of the hearing aid. The speaker converts the amplified electrical signal to sound and sends to the ear for clear hearing.
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Which separation techniques will you apply for the separation of the following?
Small pieces of metal in the engine oil of a car.
Which separation techniques will you apply for the separation of the following?
Different pigments from an extract of flower petals.
Which separation techniques will you apply for the separation of the following?
Butter from curd.
Write the steps you would use for making tea. Use the words—solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).
Substance Dissolved |
Temperature in K |
||||
283 |
293 |
313 |
333 |
353 |
|
Potassium nitrate |
21 |
32 |
62 |
106 |
107 |
Sodium chloride |
36 |
36 |
36 |
37 |
37 |
Potassium chloride |
35 |
35 |
40 |
46 |
54 |
Ammonium chloride |
24 |
37 |
41 |
55 |
66 |
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