Back to GRAVITATION

JEE PHYSICS MCQ: GRAVITATION

1 Medium

1 of 1

Understanding +4 | -1

The condition for a uniform spherical mass

m

of radius

r

to be a black hole is [G = gravitational constant and g = acceleration due to gravity]

View answer and explanation

Correct option: C

{\left( {2Gm/r} \right)^{1/2}} \ge c

Option C (

{\left( {2Gm/r} \right)^{1/2}} \ge c

) is correct because the escape velocity must be greater than or equal to the speed of light for a black hole.

More Questions from GRAVITATION

Practice All Chapter MCQs →

The escape velocity for a body projected vertically upwards from the surface of the earth is

11.2\mathrm{\;\;km}{\mathrm{s}^{ - 1}}

. If the body is projected in a direction making an angle of

{45^0}

with the vertical, the escape velocity will be The escape velocity of a body projected from the surface of earth is

v_e

. If the body is projected at an angle

\theta

to the horizontal surface of earth, then the escape velocity would be If different planets have the same density but different radii, then the acceleration due to gravity on the surface of the planet is related to the radius (R) of the planet as Which of the following statement is absolutely correct about mass Statement I: An astronaut in a satellite feels weightlessness:

Statement II: As observed by another astronaut's in the same satellite, force of gravity and centrifugal force balance each other. An iron ball and a wooden ball of the same radius are released from a height 'h' in vacuum. The time taken by both of them to reach the ground is