Question

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?

• A. The parallax of $S_1$ and $S_2$ are same.
• B. The parallax of $S_1$ is twice as that of $S_2$.
• C. The parallax of $S_1$ is greater than parallax of $S_2$
• D. The parallax of $S_2$ is greater than parallax of $S_1$

Answer 1

Answer: (D)

The parallax of $S_2$ is greater than parallax of $S_1$

$Answer:-$ D

Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.Due to foreshortning, nearby objects have a larger parallax than more distant objects when observed from different positions, so parallax can be used to determine distances.

Hence parallax of $S_2$ is greater than that of $S_1$

Astronomersuse the principle of parallax to measure distances to the closer stars. Here, the term "parallax" is the semi-angle of inclination between two sight-lines to the star, as observed when the Earth is on opposite sides of the Sun in its orbit.