Advertisements
Advertisements
प्रश्न
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.
उत्तर
Given: Angular diameter (α) = 35.72''
= 35.72'' × 4.847 × 10-6 rad
≈ 1.73 × 10-4 rad
Distance from Earth (D) = 824.7 million km
= 824.7 × 106 km
= 824.7 × 109 m.
To find: Diameter of Jupiter (d)
Formula: d = α D
Calculation: From the formula,
d = 1.73 × 10-4 × 824.7 × 109
= 1.428 × 108 m
= 1.428 × 105 km
The diameter of Jupiter is 1.428 × 105 km.
APPEARS IN
संबंधित प्रश्न
The nearest star to our solar system is 4.29 light years away. How much is this distance in terms of parsecs? How much parallax would this star (named Alpha Centauri) show when viewed from two locations of the Earth six months apart in its orbit around the Sun?
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.
Exercise
While measuring the length of an object using a ruler, the position of your eye should be
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.
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.
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?
What is the length of a 100 rupee note? Guess. Now measure it using a scale.
Difference in size
Do this for yourself and find the difference.
What is Dinesh’s height in metres? _____ m _____ cm.
Measure the yellow rectangle. It is ________ cm long.
How wide is the rectangle? ________ cm
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?
In which SI unit, you can measure your height?
Length is a fundamental quantity.
The distance between one end and the other end is called ______.
Length is ______.
What unit will you use to measure the length of our classroom?
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.