Units and Measu...

The moon is observed from two diametrically opposite points on earth. The angle subtended at the moon by the two directions of observations is $$1^o 54'$$. Given the diameter of the earth to be about $$2.276 \times 10^7 m$$, compute the distance of moon from the earth.

The mass of the electron is given $$9.1\times 10^{-31} kg$$. Find the order of magnitude of the number of electrons of $$1 kg$$.

What is the order of magnitude of the distance of a quasar from us if light takes 2.9 billion years to reach us ?  

The radius of proton is $$0.6\times 10^{-15} m$$. What is the order of magnitude of it volume?   

What is the order of magnitude of one light year? 

Match the following:

The radius of the sun is $$7\times 10^8 m$$ and its mass is $$2\times 10^{30} kg$$. What is the order of magnitude of density of the sun?

The radius of the earth is given $$6.4\times 10^6 m$$. What is the order of magnitude of the size of the earth? 

A star has a parallax angle p of 0.723 arcseconds. What is the distance of the star?

Two stars $$S_1$$ and $$S_2$$ are located at distances $$d_1$$ and $$d_2$$ respectively. Also if $$d_1>d_2$$ then which of the following statements is true?