Ncert Exercises & Solutions

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?

As we know, 1 light year = 9.46 x 10¹⁵ m
So, 4.29 light-years = 4.29 x 9.46 x 10¹⁵ = 4.058 x 10¹⁶ m
Also, 1 parsec = 3.08 x 10¹⁶ m
.So, 4.29 light-years =4.508 x 10¹⁶/3.80 x 10¹⁶ = 1.318 parsec = 1.32 parsec.
As a parsec distance subtends a parallax angle of 1″ for a basis of radius of Earth’s orbit around the Sun (r).

In the present problem, base is the distance between two locations of the Earth six months apart in its orbit around the Sun = diameter of Earth’s orbit (b = 2r).

So, Parallax angle subtended by 1-parsec distance at this basis = 2 second (by definition of parsec).
Therefore, the Parallax angle subtended by the star Alpha Centauri at the given basis θ = 1.32 x 2 = 2.64″.

NEET Information

courses

Company

Botany Questions

Chemistry Questions

Physics Questions

Zoology Questions