JEE Main Registration 2025 Session 1 (Open) - Link, Last Date, Fees, How to Apply

Relation Between Gravitational Field And Potential - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • 4 Questions around this concept.

Solve by difficulty

What is the relationship between gravitational field strength and gravitational potential?

 

Concepts Covered - 1

Relation between gravitational field and potential

 

Gravitational field and potential are related as

\vec{E}=-\frac{dV}{dr}

Where E is Gravitational field

And V is Gravitational potential

And r is the position vector 

And Negative sign indicates that in the direction of intensity the potential decreases.

 If \ \ \vec{r}=x \ \vec{i}+y \ \vec{j}+z \ \vec{k}

 

Then E_x=\frac{\delta V}{dx},E_y=\frac{\delta V}{dy},E_z=\frac{\delta V}{dz}

Proof-

Let gravitational field at a point r due to a given mass distribution is E.

If a test mass m is placed inside a uniform gravitational field E.

Then force on a particle m when it is at r is  \vec{F}=m\vec{E} as shown in figure

      

 

As the particle is displaced from r to r + dr the

work done by the gravitational force on it is

 

dW=\vec{F}.\vec{r}=m\vec{E}.d\vec{r}

The change in potential energy during this

displacement is

dU=-dW=-\vec{F}.\vec{r}=-m\vec{E}.d\vec{r}

And we know that Relation between Potential and Potential energy

As U=mV

So dV=\frac{dU}{m}= -\vec{E}.d\vec{r}

Integrating between r1, and r2

We get V(\vec{r_2})-V(\vec{r_1})= \int_{r_1}^{r_2} -\vec{E}.d\vec{r}

If r1=r0, is taken at the reference point, V(r0) = 0. 

Then the potential V(r2=r) at any point r is 

V(\vec{r}) = \int_{r_0}^{r} -\vec{E}.d\vec{r}

in Cartesian coordinates, we can write

\vec{E}=E_x \ \vec{i}+E_y \ \vec{j}+E_z \ \vec{k}

If \ \ \vec{r}=x \ \vec{i}+y \ \vec{j}+z \ \vec{k}

Then d\vec{r}=dx \ \vec{i}+dy \ \vec{j}+dz \ \vec{k}

So  

\vec{E}.d\vec{r}=-dV=E_xdx +E_ydy +E_zdz\\ dV=-E_xdx -E_ydy -E_zdz

If y and z remain constant, dy = dz = 0

Thus E_x=\frac{dV}{dx}

Similarly E_y=\frac{dV}{dy}, E_z=\frac{dV}{dz}

Study it with Videos

Relation between gravitational field and potential

"Stay in the loop. Receive exam news, study resources, and expert advice!"

Get Answer to all your questions

Back to top