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प्रश्न
Now guess the length and width of many other things. Measure and find the difference between your measure and your guess.
| Size of | Your guess in cm | Your measure in cm | ||
| Length | Width | Length | Width | |
| 100 Rupee note | ||||
| 10 Rupee note | ||||
| 20 Rupee note | ||||
| 5 Rupee note | ||||
| Post card | ||||
| Math-Magic book | ||||
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उत्तर
| Size of | Your guess in cm | Your measure in cm | ||
| Length | Width | Length | Width | |
| 100 Rupee note | 16.2 | 7.0 | 15.5 | 7.3 |
| 10 Rupee note | 13.0 | 6.0 | 13.7 | 6.3 |
| 20 Rupee note | 15.0 | 6.5 | 14.8 | 6.3 |
| 5 Rupee note | 11.5 | 6.5 | 11.7 | 6.3 |
| Post card | 14.0 | 9.0 | 14.5 | 9.5 |
| Math-Magic book | 28.0 | 22.0 | 28.5 | 21.5 |
Difference between my guess and measurement
| Size of | Difference in cm | |
| Length | Width | |
| 100 Rupee note | 0.5 cm | 0.3 cm |
| 10 Rupee note | 0.7 cm | 0.3 cm |
| 20 Rupee note | 0.2 cm | 0.2 cm |
| 5 Rupee note | 0.5 cm | 0.2 cm |
| Post card | 0.5 cm | 0.5 cm |
| Math-Magic book | 0.5 cm | 0.5 cm |
संबंधित प्रश्न
Match the following.
| Column A | Column B |
| (1) Length | a. kilogram |
| (2) Mass | b. cubic metre |
| (3) Area | c. metre |
| (4) Volume | d. square metre |
Length of one’s chest can be measured using metre scale.
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 |
Which line is longer? C or D? Measure each line. How good is your guess?
What is the length of a 100 rupee note? Guess. Now measure it using a scale.
Measure the yellow rectangle. It is ________ cm long.
How many stamps can be placed along its length?
How many stamps are needed to cover the rectangle?
The fencing of a square garden is 20 m in length. How long is one side of the garden?
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)
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.
- How many kilometers long is the actual boundary of lake B?
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?
What is the unit of length?
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?
How many astronomical units (A.U.) make 1 parsec?
Consider a sunlike star at a distance of 2 parsecs. When it is seen through a telescope with 100 magnification, what should be the angular size of the star? Sun appears to be (1/2)° from the earth. Due to atmospheric fluctuations, eye can’t resolve objects smaller than 1 arc minute.
What is the SI unit of length?
The parallax method is used to measure astronomical distances because ______.
