NEET Physics Gravitation MCQs

A perfectly spherical planet X has twice the radius of Earth and half the average density. An object weighs 100 N on Earth's surface. What would be its weight on the surface of planet X?

Imagine a planet with a non-uniform density distribution. Its core has a density $\rho_c$, and the outer shell has a density $\rho_s$. If the core radius is half the total radius R, what core density $\rho_c$ would result in the same surface gravity as Earth (assuming the shell density $\rho_s$ is negligible)?

If Earth's density were doubled while its radius remained constant, the acceleration due to gravity at its surface would:

If Earth's radius were doubled while its mass remained constant, the acceleration due to gravity at its surface would:

A planet has a radius R and density $\rho$. If both are doubled, the acceleration due to gravity at its surface will:

At what height above the Earth's surface is the acceleration due to gravity half of its value at the surface? (R is the radius of Earth)

A binary star system consists of two stars, A and B, with masses $M_A$ and $M_B$ respectively, separated by a distance $d$. Star A is four times more massive than star B ($M_A = 4M_B$). Both stars orbit their common center of mass. If the period of their orbit is $T$, what is the period of a hypothetical planet of negligible mass orbiting star A at a distance of $\frac{d}{2}$?

A binary star system consists of two stars of masses $M$ and $2M$ separated by a distance $d$. A small asteroid of mass $m$ is placed on the line joining the two stars at a distance $x$ from the star of mass $M$. If the net gravitational force on the asteroid is zero, what is the ratio $x/d$?

A spherical shell of uniform mass density $\rho$ and inner radius $R_1$ and outer radius $R_2$ exerts a gravitational force on a point mass $m$ located at a distance $r$ from the center. Which of the following expressions correctly represents the gravitational field strength experienced by the point mass when $R_1 < r < R_2$?

Two concentric spherical shells of mass $M_1$ and $M_2$ and radii $R_1$ and $R_2$ ($R_2 > R_1$) respectively, are placed in free space. The gravitational potential at a distance $r$ such that $R_1 < r < R_2$, from the center is: