Advertisements
Advertisements
Question
Which line is longer? C or D? Measure each line. How good is your guess?

Advertisements
Solution
I think both lines C and D are of the same measurement.
With the help of a ruler, we get the measurement of 3.2 cm for both lines.
So, our guess was correct.
APPEARS IN
RELATED QUESTIONS
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 strands of hair on your head
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?
Complete the analogy.
Height of a person: cm :: Length of your sharpened pencil lead:______?
Numerical Problem.
Inian and Ezhilan argue about the light year. Inian tells that it is 9.46 × 1015 m and Ezhilan argues that it is 9.46 × 10 12 km. Who is right? Justify your answer.
Measure the yellow rectangle. It is ________ cm long.
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.

- Find the area of lake B on the drawing in square cm. What is its actual area in square km?
What formula is used to measure the area of your classroom?
Match the following:
| Prefix | Symbol | ||
| a. | Centi | i. | k |
| b. | Nano | ii. | c |
| c. | Mili | iii. | n |
| d. | Kilo | iv. | m |
What is the unit of measurements of very small lengths?
What is the unit of length?
Yard was used as the unit of length.
The SI unit of mass is kg.
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 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.
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.
Why is Earth's orbit used instead of its diameter to measure distances to stars using the parallax method?
