Question

1parsec =.........metres

Answer 1

Hint:$\text{Metre}$ is a unit of length and as such $\text{parsec}$ is a unit of length, used to measure large distances, so the value of $\text{1parsec}$ should be very large in metres. It is used in case of astronomy, so the value should be of the scale of distances in case of astronomical objects.


Complete step by step solution:
Definition: The $\text{parsec}$ is a unit of length used to measure large distances, in between astronomical objects situated outside the solar system to objects present inside the system. A $\text{parsec}$ is obtained by the use of parallax and trigonometry. Physically, a $\text{parsec}$ is defined as the distance at which one astronomical unit subtends an angle of one $\text{arcsecond}$. The unit $\text{parsec}$ was first suggested by the British astronomer Herbert Hall Turner.
$\text{1 parsec}$ is about $31$ trillion $\text{kilometres}$, which when converted to metres become $3.08\times {{10}^{16}}metres$, which is actually a very large distance.


Therefore, the answer to the given question is, $1par\sec =3.08\times {{10}^{16}}metres$.

Additional Information:
1. The nearest star ‘Proxima Centauri’ is about $\text{1}\text{.3parsecs}$ from the sun. The general representation of the unit $\text{parsec}$ is $pc$.
2. $1arc\sec ond=\dfrac{1}{3600}$ of a $\deg ree$.
3. In SI units, $1par\sec =3.08\times {{10}^{16}}metres$.
4. In imperial or US units, $1par\sec =1.9174\times {{10}^{13}}miles(mi)$.
5. In astronomical units, $1par\sec =2.06265\times {{10}^{5}}au$.

If calculated in light years ($ly$), which is also a unit of length, $1par\sec =3.26156ly$.


Note:Students must be very careful about the powers to which $10$ is raised because even a simple modification in the power might lead to a large difference. Students must also be careful about the units of measurements, and if there arises any confusion, they can verify their units using dimensional analysis.