Question

Parallactic second is a unit of:
A. Time
B. Speed
C. Distance
D. None of these

Answer 1

Hint: Parallactic second an abbreviation of parsec is a unit used by astronomers.
1 parsec= 3.26 lightyears.

Complete step by step answer:
Parallactic second or parsec is a unit of large distances used by the astronomers to measure large distances outside our solar system.
One parsec is defined as the distance between the line drawn from the centre of the Earth and the Sun making an angle of 1 second with each other. In other words, it’s the distance at which a star would make a parallax of one second of arc.
So, the correct answer is option C. distance.

Additional Information:
One parsec is approximately equal to 31 trillion km ($3.1\times {{10}^{16}}m$) or 19 trillion miles. The nearest star in our solar system Proxima Centauri is about 1.3 parsecs or 4.2 lightyears away from the sun. Most of the stars visible to us in the night sky are within a radius of 500 parsecs of the sun. This unit was first used in 1913 by a British astronomer to make calculations quick and easy for astronomers. It is more popularly used by astronomers and astrophysicists while light years is a more commonly used scientific term.
One lightyear is approximately = $9.461\times {{10}^{15}}m$

Note: Students should confuse it as a unit of time. Although the name says second but it's not a unit of time just like lightyears it’s a unit of distance.