When a star collapses to half size,the gravitational field at its surface
A)doubles.
B)quadruples.
C)increases eightfold.
D)remains constant.

Question

Quizplus · Accepted Answer

The surface of a star is where the gravitational field is measured from. The strength of the gravitational field is directly proportional to the mass of the object and inversely proportional to the square of the distance. Since the star has collapsed to half its original radius, the distance from the surface to the center of mass (and hence the distance the measurement is taken from) has been reduced to a quarter of the original distance. Therefore, since the mass of the star has not changed, the gravitational field strength at the surface has quadrupled.

When a Star Collapses to Half Size,the Gravitational Field at Its