Advertisements
Advertisements
प्रश्न
You can play this game on the ground. Make two squares of one square meter each. Divide your class into two teams. Ready to play!
- How many of you can stand in it?
Advertisements
उत्तर
Four can stand in it.
APPEARS IN
संबंधित प्रश्न
The farthest objects in our Universe discovered by modern astronomers are so distant that light emitted by them takes billions of years to reach the Earth. These objects (known as quasars) have many puzzling features, which have not yet been satisfactorily explained. What is the distance in km of a quasar from which light takes 3.0 billion years to reach us?
When the planet Jupiter is at a distance of 824.7 million kilometres from the Earth, its angular diameter is measured to be 35.72″ of arc. Calculate the diameter of Jupiter
Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):-
the number of air molecules in your classroom.
500 gm = ______ kilogram.
Match the following.
| 1. | Length of the fore arm | metre |
| 2. | SI unit of length | second |
| 3. | Nano | 103 |
| 4. | SI Unit of time | 10–9 |
| 5. | Kilo | Cubit |
Metre is the unit of ______.
Have you seen frogs? Where? How many different types of frogs have you seen? Are all the frogs of the same length? Here are two interesting examples.
Which line is longer? C or D? Measure each line. How good is your guess?
What is Dinesh’s height in metres? _____ m _____ cm.
Measure the yellow rectangle. It is ________ cm long.
Chumki, Jhumri, and Imran need wire to make a fence.
- How much wire in all will the three need?
There are two beautiful lakes near a village. People come for boating and picnics in both the lakes. The village Panchayat is worried that with the noise of the boats the birds will stop coming. The Panchayat wants motorboats in only one lake. The other lake will be saved for the birds to make their nests.
- How many cm is the length of the boundary of lake A in the drawing?(use thread to find out)
What are the materials needed to find the length of a banana?
What is the unit of measurements of very small lengths?
The distance between one end and the other end is called ______.
What unit will you use to measure the length of our classroom?
Yard was used as the unit of length.
- The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?
- Moon is seen to be of (½)°diameter from the earth. What must be the relative size compared to the earth?
- From parallax measurement, the sun is found to be at a distance of about 400 times the earth-moon distance. Estimate the ratio of sun-earth diameters.
In an experiment to estimate the size of a molecule of oleic acid 1 mL of oleic acid is dissolved in 19 mL of alcohol. Then 1 mL of this solution is diluted to 20 mL by adding alcohol. Now 1 drop of this diluted solution is placed on water in a shallow trough. The solution spreads over the surface of water forming one molecule thick layer. Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule.
Read the passage carefully and answer the following questions:
- Why do we dissolve oleic acid in alcohol?
- What is the role of lycopodium powder?
- What would be the volume of oleic acid in each mL of solution prepared?
- How will you calculate the volume of n drops of this solution of oleic acid?
- What will be the volume of oleic acid in one drop of this solution?
Mars has approximately half of the earth’s diameter. When it is closest to the earth it is at about 1/2 A.U. from the earth. Calculate what size it will appear when seen through the same telescope.
