Height of geostationary satellite is

• 16000 km

• 22000 km

• 28000 km

• 36000 km

Assertion:  An astronaut experience weightlessness in a space satellite. 

Reason:  When a body falls freely it does not experience gravity.

• If both assertion and reason are true and reason s the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion: A man in a closed cabin which is falling freely does not experience gravity.

Reason: Inertial and gravitational mass have equivalence.

• If both assertion and reason are true and reason is the correct explanation of the assertion

• If both assertion and reason are true but reason is not the correct explanation of the assertion

• If assertion is true, but reason is false

• Both assertion and reason are false statements.

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 ]

• ${\left(\frac{2 \mathrm{Gm}}{\mathrm{r}}\right)}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \le \mathrm{c}$

• ${\left(\frac{2 \mathrm{gm}}{\mathrm{r}}\right)}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} = \mathrm{c}$

• ${\left(\frac{2 \mathrm{Gm}}{\mathrm{r}}\right)}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right. } \ge \mathrm{c}$

• ${\left(\frac{\mathrm{gm}}{\mathrm{r}}\right)}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \ge \mathrm{c}$

The velocity with which a projectile must be fired so that it escapes earth's gravitation does not depend on

• mass of the earth

• mass of the projectile

• radius of the projectile's orbit

• gravitational constant

166.

Hubble's law is related with

• comet

• speed of galaxy

• black hole

• planetary motion

Kepler's second law is based on

• Newton's first law

• special theory of relativity

• Newton's second law

• Conservation of angular momentum

If  v_ο be the orbital velocity of satellite in a circular orbit close to the earth's surface and  v_e  is the escape  velocity from the earth, then relation between the two is

• v_ο  = v_e

• v_e =  $\sqrt{3} {\mathrm{v}}_{\mathrm{o}}$

• v_e =  $\sqrt{2}$ v_ο

• v_e = 2 v_ο

Assertion:  Planet is a heavenly body revolving round the sun. 

Reason: Star is luminous body made of gaseous material.

• If both the assertion and reason are true and reason is a correct explanation of the assertion.

• If both assertion and reason are true but assertion is not a correct explanation of the assertion.

• If the assertion is true but the reason is false.

• If both assertion and reason are false.

The orbital velocity of an artificial satellite in a circular orbit above the earth's surface at a distance equal to radius of earth is v. For a satellite orbiting at an altitude half of earth's radius, orbital velocity is

• $\frac{3}{2}$v

• $\sqrt{\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$2$}\right.} \mathrm{v}$

• $\frac{2}{\sqrt{3}}$v

• $\frac{2}{3}$v