It is a well known fact that during a total solar eclipse the disc of the moon almost covers the disc of the sun. Find the approx. diameter of moon from the following data.

During a total solar eclips the moon almost entirely covers the sphere of the sun. Write the relation between the distances and sizes of the sun and moon.

Kunal is curious to find out the relationship between the diameter o the moon and the earth. From the available data, it is know that the volume of earth is 64 times the volume of the moon. He concluded that the diameter of the moon is 1/4 of the diameter of the earth. Show did he arrive at the conclusions?

At the time of solar eclipse,the light from the entire sun is cut off,although its diameter is several hundred times larger than that of the moon.Why?

When observed from the earth,the angular diameter of the solar disc is 32 minutes of arc .Determne the diameter of the image of the sun formed by a convex lens of focal length 25 cm.

Answer the following :- If you compare the gravitational force on the earth due to the sun to that due to the moon, you would find that the Sun’s pull is greater than the moon’s pull. (you can check this yourself using the data available in the succeeding exercises). However, the tidal effect of the moon’s pull is greater than the tidal effect of sun. Why ?

Observe the following facts : (1) The distance from the Earth to the Sun is 149,600,000,000m (2)The speed of light is 300,000,000 m/sec. (3) Thickness of class VII Mathematics book is 20mm (4) The average diameter of a Red Blood cell is 0.00007mm. (5) The thickness of human hair is in the range of 0.005 cm to 0.01 cm. (6) The distance of moon from the Earth is 384,467,000 m. (approx.) (7) The size of a plant cell is 0.00001275m. (8) Average radius of the Sun is 695000km. (9) Mass of propellant in a space shuttle solid rocket booster is 503600kg (10) Thickness of a piece or paper is 0.0016cm. (11) Diameter of a wire on a computer chip is 0.000003m. (12) The height of Mount Everest is 8848m. There some large number like 150,000,000,000m and some every small numbers like 0.000007m. Identify very large and very small numbers from the above facts and write them in the adjacent table.