10 Question-answer on Kepler's law
1. Kepler III law i.e. T2 is proportional to R3, is a consequence of law of conservation of:
(a) Linear momentum
(b) Angular momentum
(c) Energy
(d) Law of quantization of angular momentum
Ans: ( b)
2. A geostationary satellite is orbiting the earth at a height 6R above the surface of earth, where R is radius of earth. The time period of another satellite at a height 2.5 R from the earth surface would be:
(a) 24 hrs
(b) 6/2.5 hrs
(c) 2.5/6 hrs
(d) 6√2 hrs
Ans: (d)
3. The time period of a satellite in a circular orbit of radius R is T. The radius of the orbit in which time period is 8 T is:
(a) 2R
(b) 3R
(c) 4R
(d) 5R
Ans: ( c)
4. Kepler’s second law states that the straight line joining the planate to the sun sweeps out equal areas in equal times. This statement is equivalent to saying that:
(a) Total acceleration is zero
(b) Transverse acceleration is zero
(c) Tangential acceleration is zero
(d) Radial acceleration is zero
Ans: ( b,c)
5. If the earth is at one fourth of its present distance from the sun, the duration of the year will be change by:
(a) Half the present year
(b) One-eighth of the present year
(c) seventh-eight of the present year
(d) One-fourth of the present year
Ans: ( c)
6. The distance of the planet is 5.2 times the distance of earth from sun. What will be approximate period of planet round the sun?
(a) 1 year
(b) 3 year
(c) 6 year
(d) 12 year
Ans: ( d)
7. If the mean distance of mars from the sun is 1.525 times that of the earth from the sun. In how many years Mars will complete one revolution about the sun
(a) 1.883
(b) 2
(c) 3.766
(d) 4.
Ans: ( a)
8. A satellite is orbiting a planet at a certain height in a circular orbit. If the mass of the planet is suddenly reduced to half, the satellite would:
(a) Continue to revolve round the planet
(b) Freely fall on the planet
(c) Orbital velocity decreased
(d) Escape from the planet
Ans: (a)
9. What is the ratio of gravitational mass and inertial mass:
(a) ½
(b) 1
(c) 2
(d) Not fixed
Ans: ( b)
2. A planet is revolving round the sun in an elliptical orbit. The work done on the planet by the gravitational force of sun is zero:
(a) In some parts of the orbit
(b) In any part of the orbit
(c) In no part of the orbit
(d) In one complete revolution
Ans: (a,d)