Advertisements
Advertisements
Question
Mars has approximately half of the earth’s diameter. When it is closest to the earth it is at about 1/2 A.U. from the earth. Calculate what size it will appear when seen through the same telescope.
Advertisements
Solution
Given that `D_("mars")/D_("earth") = 1/2` .....(i)
Where D represents the diameter.
We know that, `D_("earth")/D_("sun") = 1/100`
∴ `D_("mars")/D_("sun") = 1/2 xx 1/100` ......[From equation (i)]
At 1 A.U sun's diameter = `(1/2)^circ`
∴ Diameter of mars = `1/2 xx 1/200 = (1/400)^circ`
At `1/2` A.u, Mar's diameter
= `1/400 xx 2^circ = (1/200)^circ`
With 100 magnification mar's diameter
= `1/200 xx 100^circ = (1/2)^circ` = 30
This is larger than the resolution limit due to atmosphere fluctuations.
Hence, it looks magnified.
APPEARS IN
RELATED QUESTIONS
Write true or false.
Every measurement involves two things – a number and a unit.
While measuring the length of a sharpened pencil, the reading of the scale at one end is 2.0 cm and at the other end is 12.1 cm. What is the length of the pencil?
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.
Rulers, measuring tapes and metre scales are used to measure ______
Can you find the diameter of a thin wire of length 2 m using the ruler from your instrument box?
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.

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

Guess whose tail is the longest. Now measure the tails. How good is your guess?






How close was your earlier guess? Discuss.
Arbaz plans to tile his kitchen floor with green square tiles. Each side of the tile is 10 cm. His kitchen is 220 cm in length and 180 cm wide. How many tiles will he need?

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.

- What is the length of the boundary of lake B in the drawing?
Length is a fundamental quantity.
Give some examples of larger length measures.
The distance between one end and the other end is called ______.
The Unit used to measure length ______.
To measure the distance of a planet from the earth, ______ method is used.
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?
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.
