Assertion (A): | The orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth. |
Reason (R): | The orbital velocity of a satellite is greater than its escape velocity. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Assertion (A): | Generally the path of a projectile from the Earth is parabolic but it is elliptical for a projectile going to a very great height. |
Reason (R): | At the ordinary height, the projectile moves under a uniform gravitational force, but for great heights, the projectile moves under a variable force. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | Both (A) and (R) are False. |
Assertion (A): | The angular velocity of a planet orbiting around the sun increases when it is nearest to the sun. |
Reason (R): | Angular momentum of a body is proportional to angular velocity. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | A body becomes weightless at the centre of the earth. |
Reason (R): | As the distance from the centre of earth decreases, acceleration due to gravity increases. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The binding energy of a satellite depends upon the mass of the satellite. |
Reason (R): | Binding energy is the negative value of the total energy of a satellite. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The speed of revolution of an artificial satellite revolving very near the earth is 8 kms-1. |
Reason (R): | Orbital velocity of a satellite becomes independent of the height of the satellite. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The length of the day is slowly increasing. |
Reason (R): | The dominant effect causing a slowdown in the rotation of the earth is the gravitational pull of other planets in the solar system. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion(A): | A planet moves faster when it is closer to the sun in its orbit and vice-versa. |
Reason(R): | Orbital velocity in the orbit of the planet is constant. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The comets do not obey Kepler's law of planetary motion. |
Reason (R): | The comets do not have elliptical orbits. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | The square of the period of revolution of a planet is proportional to the cube of the semi-major axis of its elliptical orbit. |
Reason (R): | Sun's gravitational field is inversely proportional to the square of its distance from the planet. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |