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प्रश्न
Can you think of how to cut a postcard so that you can pass through it?
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उत्तर
Yes, I can pass through a postcard by making a loop from it.
The steps are given below:
Make lines on the postcard as shown in this figure.
Cut the postcard along the lines which touch its border.
This will make a loop as shown here.
संबंधित प्रश्न
The principle of ‘parallax’ in section 2.3.1 is used in the determination of distances of very distant stars. The baseline AB is the line joining the Earth’s two locations six months apart in its orbit around the Sun. That is, the baseline is about the diameter of the Earth’s orbit ≈ 3 × 1011m. However, even the nearest stars are so distant that with such a long baseline, they show parallax only of the order of 1” (second) of arc or so. A parsec is a convenient unit of length on the astronomical scale. It is the distance of an object that will show a parallax of 1” (second) of arc from opposite ends of a baseline equal to the distance from the Earth to the Sun. How much is a parsec in terms of meters?
What are the S.I. units of
- mass
- length
- time and
- temperature.
Write their names and symbols.
Answer the following question.
Star A is farther than star B. Which star will have a large parallax angle?
Length of one’s chest can be measured using metre scale.
Find the answer for the following questions within the grid.
- 10-3 is one ______
- SI Unit of time is ______
- Cross view of reading a measurement leads to ______
- ______ is the one what a clock reads.
- ______ is the amount of substance present in an object.
- ______ can be taken to get the final reading of the recordings of different students for a single measurement.
- ______ is a fundamental quantity.
- ______ shows the distance covered by an automobile
- A tailor uses ______ to take measurements to stitch the cloth.
- Liquids are measured with this physical quantity.
Which line is longer? C or D? Measure each line. How good is your guess?
The fencing of a square garden is 20 m in length. How long is one side of the garden?
Now cut strips of equal sizes out of it. Using tape join the strips, end to end, to make a belt.
How long is your belt? _________
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 sit in one square meter?
So Anar also tried many different ways to make a boundary for 800 square meters of land.
He made rectangles A, B, and C of different sizes. Find out the length of the boundary of each. How much gold wire will he get for these rectangles?
- A
Gold wire for A = _________ metres - B
Gold wire for B = _________ metres - C
Gold wire for C = __________ metres
But then Anar made an even longer rectangle... See how long!
- D
So he will get __________ metres of gold wire!!
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.
- A longer boundary around the lake will help more birds to lay their eggs. So which lake should be kept for birds? Which lake should be used for boats?
Length is a fundamental quantity.
What are the materials needed to find the length of a banana?
What is the unit of measurements of very small lengths?
The radius of atom is of the order of 1 Å and the radius of nucleus is of the order of fermi. How many magnitudes higher is the volume of atom as compared to the volume of nucleus?
The distance of a galaxy is of the order of 1025 m. Calculate the order of magnitude of time taken by light to reach us from the galaxy.
How many astronomical units (A.U.) make 1 parsec?
What is an Astronomical Unit (AU)?
Which instruments are used to measure very small distances at the atomic scale?
