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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 |
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संबंधित प्रश्न
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.
Write true or false.
Every measurement involves two things – a number and a unit.
Solve the numerical example.
When the planet Jupiter is at a distance of 824.7 million kilometers from the Earth, its angular diameter is measured to be 35.72'' of arc. Calculate the diameter of Jupiter.
A hand span is a reliable measure of length.
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 |
Fill in the following chart.
| Property | Definition | Basic Unit | Instrument used for measuring |
| Length | |||
| Mass | |||
| Volume | |||
| Time |
Metre is the unit of ______.
Can you find the diameter of a thin wire of length 2 m using the ruler from your instrument box?
Guess the lengths to draw these things. Ask your friend to draw the same. After you make the drawing use a scale to measure the length. Whose drawing showed a better guess?
| Guess its length and draw |
Measure of your drawing |
Measure of your friend’s drawing |
| An ant of length less than 1 cm |
||
| Pencil of length about 7 cm |
||
| A glass 11 cm high with water up to 5 cm |
||
| A bangle of perimeter 20 cm |
||
| A curly hair of length 16 cm |
Guess whose tail is the longest. Now measure the tails. How good is your guess?






Measure the yellow rectangle. It is ________ cm long.
How close was your earlier guess? Discuss.
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? _________
Length is a fundamental quantity.
What formula is used to measure the area of your classroom?
What is the unit of length?
SI unit of electric current is ______.
Larger unit for measuring time is ______.
The SI unit of mass is kg.
Why is Earth's orbit used instead of its diameter to measure distances to stars using the parallax method?
