JEE PHYSICS MCQ: GRAVITATION

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Assertion: For circular orbits, the law of periods is

{T}^2 \propto {r}^3

, where

{M}

is the mass of sun and

r

is the radius of orbit.
Reason: The square of the period

T

of any planet about the sun is proportional to the cube of the semi-major axis

a

of the orbit.

View answer and explanation

Correct option: A

If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion

Option A is correct because Kepler's Third Law states that the square of the period is proportional to the cube of the semi-major axis, which applies to circular orbits as well.

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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

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