Question

The units of gravitational field in Si units is -
A. N/m
B. N/C
C. N/kg
D. N/gm

Answer 1

- Gravitational field = Gravitational force/mass
- So, (SI unit of Gravitational field) = (SI unit of gravitational force)/(SI unit of Mass)
- SI unit of Gravitational force is N.
- SI unit of mass is kg.

Complete step by step solution:
Gravitational field due to any object at a certain distance is defined as the gravitational force on any unit mass due to that object at that point.

According to Newton’s law of gravitation, The gravitational force between two objects of mass $M$and $m$ separated at a distance $r$, is $F = \dfrac{{GMm}}{{{r^2}}}$.

So, if we put $m = 1$ then according to the definition we will get the gravitational field due to an object of mass $M$ at a distance $r$ and that is$E = \dfrac{{GM}}{{{r^2}}}$..
So, gravitational field = (Gravitational force)/mass
Or (SI unit of Gravitational field) = (SI unit of gravitational force)/(SI unit of Mass)
Now, the gravitational force is another type of force. So, the SI unit of gravitational force will be the same as the SI unit of force which is N (newton).
And, the SI unit of mass is kg.
So, the SI unit of gravitational field will be = N/kg

Correct option is (C)

Note: The gravitational force between two objects of mass $M$and $m$ separated at a distance $r$, is $F = \dfrac{{GMm}}{{{r^2}}}$.
The gravitational field due to an object of mass $M$at a distance $r$is $E = \dfrac{{GM}}{{{r^2}}}$.
- Gravitational field = $\dfrac{{gravitational{\text{ }}force}}{{mass}}$
- Basically, Gravitational field is used to explain the influence of an object around it.
- We can state that whenever any object comes in the influence of any other object it will feel gravitational force due to the gravitational field of the other object.