Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why?
The speed of sound which is equal to 344 ms–1 is much smaller than the speed of light, equal to 3 x 108 ms–1. Therefore, thunder is heard a few seconds after the lightning flash is seen.
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 |
Mock Test Series
