NEET Free Online Mock Test - 2019
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NEET Physics Gravitation Practice Q & A
1. If ‘r’ represents the radius of the orbit of a satellite of mass ‘m’ moving round a planet of mass ‘M’, the velocity of the satellite is given by
v^{2} = $\dfrac{gM}{r}$ | v^{2} = $\dfrac{GMm}{r}$ | v = $\sqrt{\dfrac{GM}{r}}$ | v = $\dfrac{GM}{r^{2}}$ |
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2. When the planet comes nearer the sun moves
fast | slow | constant at every point | none of the above |
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3. Kepler’s second law regarding constancy of arial velocity of a planet is a consequence of the law of conservation of
energy | angular momentum | linear momentum | none of these |
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4. The relation between escape velocity and orbit velocity is
v_{e} = $\sqrt{2v}_{orb}$ | v_{e} = $\dfrac{1}{\sqrt{2}}v_{orb}$ | v_{e} = $2v_{orb}$ | v_{e} = $\sqrt{3}v_{orb}$ |
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5. A geostationary satellite is orbiting the earth at a height of 6R above the surface of the earth, R being the radius of the earth. The time period of another satellite at a height of 2.5 R from the surface of earth is
6$\sqrt{2}$ hr | 6 hr | 5$\sqrt{2}$ hr | 10 hr |
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6. The distance of Neptune and Saturn from the sun are nearly 1013 m and 1012 m respectively. Assuming that they move in circular orbits, their periodic times would be in the ratio of
10 | 100 | 10 $\sqrt{10}$ | 1000 |
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7. Imagine a light planet revolving around a very massive star in a circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between the planet and the star is proportional to R^{-5/2} then
T^{2} \propto R^{2} | T^{2} \propto R^{7/2} | T^{2} \propto R^{3/2} | T^{2} \propto R^{3} |
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8. The acceleration due to gravity g and mean density of the earth ρ are related by which of
the following relation? Where g is gravitational constant and R is radius of the earth
ρ = $\dfrac{4\pi gR^{2}}{3G}$ | ρ = $\dfrac{4\pi gR^{3}}{3G}$ | ρ = $\dfrac{3g}{4\pi GR}$ | ρ = $\dfrac{3g}{4\pi GR^{3}}$ |
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9. If the earth is 1/4^{th} of its present distance from the sun, the duration of the year would be
1/4 of the present year | 1/6 of the present year | 1/8 of the present year | 1/16 of the present year |
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10. A planet has twice the radius but the mean density is 1/4^{th} as compared to earth. What is the radio of the escape velocity from the earth to that from the planet?
3 : 1 | 1 : 2 | 1 : 1 | 2 : 1 |
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