Assertion (A): Escape velocity of a satellite is greater than its orbital velocity.
Reason (R): Orbit of a satellite is within the gravitational field of planet whereas escaping is beyond the gravitational field of planet.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Assertion (A) is true: escape velocity \(V_e = \sqrt{2GM/r}\) is \(\sqrt{2}\) times orbital velocity \(V_o = \sqrt{GM/r}\) for a circular orbit.
Reason (R) is false because the gravitational field extends infinitely. Escaping means overcoming the gravitational potential, not leaving the field.
Assertion (A): Comet tail points away from the sun.
Reason (R): Solar radiation vapourise the volatile materials within the comet.
1. Both (A) \(&\) (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) \(&\) (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
The comet tail always points away from the Sun due to solar wind and radiation pressure pushing on the sublimated material. Solar radiation does vaporize volatile materials, forming the tail, but this vaporization itself doesn't fully explain the direction. Hence, both statements are true, but R is not the correct explanation of A.