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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1601. |
With two characteristics of gravitational force? |
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Answer» (1) It is a central force (2) It is a conservation force (3) It obeys inverse square law. (4) It is a universal force and is always attractive in nature |
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| 1602. |
Which is not correct about escape velocity?A. Escape velocity of a body depends on its mass.B. Escape velocity of a body is greater than its orbital velocity.C. Escape velocity of a body is different on different planets.D. Escape velocity of a body on a planet depends on the mass of the planet. |
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Answer» Correct Answer - A Escape velocity of a body is independent of its mass. |
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| 1603. |
The value of quantity of G in the law of gravitationA. depends on mass of earth onlyB. depends on radius of earth onlyC. depends on both mass and radius of earthD. is independent of mass and radius of the earth |
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Answer» Correct Answer - D In the law of gravitation ,value of G does not depend upon mass and radius of earth. |
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| 1604. |
The line joining the centre of gravity of a cuboid and the centre of the Earth will fall within the base of the body even after being disturbed by an external force. Then the body is said to be in _____.A. neutral equilibriumB. stable equilibriumC. unstable equilibriumD. dynamic equilibrium |
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Answer» Correct Answer - B If the line joining centre of gravity of the body and the centre of the Earth passes throught the base of the body, the body regains its position after being disturbed. Thus, the body is in stable equilibrium. |
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| 1605. |
The force of attraction between two unit point masses separted by a unit distance is calledA. gravitational potentialB. accelerationa due to gravityC. gravitational fieldD. universal gravitational constant |
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Answer» Correct Answer - D Form `F=(Gm_(1)m_(2))/d^(2)` When `m_(1)=m_(2)=(1) and d =(1)`, `F=(Gxx1xx1)/(1)^(2)=G`, i.e., force of attraction =universal gravitational constant. |
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| 1606. |
Given that `d_(e), d_(m)` are densities of the Earth and moon, respectively, `D_(e), D_(m)` are the diameters of the Earth and the moon, respectively. `g_(e) "and" g_(m)` are the acceleration due to gravity on the surface of the Earth and moon, respectively. Find the ratio of `g_(m) "and" g_(e)` |
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Answer» Acceleration due to gravity on the surface of the Earth and the moon be `g_(E) "and" g_(M)` and its mass and radius be `M_(e), R_(e) "and" M_(m), R_(m)`, respectively. `(g_(E))/(gm)=(GM_(E))/(R_(e)^(2)) xx (R_(m)^(2))/(GM_(m))` Here, diameters of the Earth and the moon are `D_(E) "and" D_(m)`, respectively. Then, `R_(e) =(D_(e))/(2) "and" R_(m) = (D_(m))/(2)` Find the relation between acceleration due to gravity on the Earth and on the moon with their diameters. |
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| 1607. |
What is represented by G ? What is its value on moon ? |
| Answer» G represents univerasal gravitational constant. `G6.67xx10^(-11)Nm^(2)kg^(-2)`, the value is fixed all over the universe. | |
| 1608. |
Two bodies, one of mass 1 gram and other of mass 1 kiliogram are dropped are dropped from the same height.which one will hit the ground first ? |
| Answer» Both will hit the ground simultaneously because for both,`u=0 and a =g`. | |
| 1609. |
If ve and vo represent the escape velocity and orbital velocity of a satellite corresponding to a circular orbit of radius R respectively, then(A) ve = vo(B) \(\sqrt{2}\)vo = ve(C) ve = \(\frac{1}{\sqrt{2}}\)vo(D) ve and vo are not related |
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Answer» Correct option is: (B) \(\sqrt{2}\)vo = ve |
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| 1610. |
If gravitational force of Earth disappears, what will happen to the satellite revolving round the Earth?(A) Satellite will come back to Earth. (B) Satellite will continue to revolve. (C) Satellite will escape in tangential path. (D) Satellite will start falling towards centre. |
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Answer» (C) Satellite will escape in tangential path. |
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| 1611. |
Potential energy of a body in the gravitational field of planet is zero. The body must be(A) at centre of planet. (B) on the surface of planet. (C) at infinity. (D) at distance equal to radius of Earth. |
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Answer» Correct option is: (C) at infinity. |
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| 1612. |
If the escape velocity of a body on Earth is 11.2 km/s, the escape velocity of the body thrown at an angle 45° with the horizontal will be(A) 11.2 km/s(B) 22.4 km/s(C) \(\frac{11.2}{\sqrt{2}}\) km/s(D) 11.2 \(\sqrt{2}\) km/s |
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Answer» Correct option is: (A) 11.2 km/s Escape velocity does not depend on the angle of projection. \(V_{escape} = \sqrt {2gRe} \) Correct option is: (A) 11.2 km/s |
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| 1613. |
The escape velocity of a satellite from the surface of a planet is `sqrt(2)` times the orbital velocity of the satellite. If the ratio of the masses of two given planets is 1 : 4 and that of their radii is 1 : 2, respectively, then find the ratio of escape velocities of a satellite from the surfaces of two planets. |
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Answer» (i) `V_(e) = sqrt(2) xx V_(o)` `F = (GMm)/(R^(2)) = (mv_(o)^(2))/(R)` `v_(o) = sqrt((GM)/(R))` `rArr (v_(e1))/(v_(e2)) = (sqrt(2)v_(o1))/(sqrt(2)v_(o1))=sqrt((M_(1))/(R_(1)) xx (R_(2))/(M_(2)))` Given that, `rArr (M_(1))/(M_(2)) = (1)/(4) "and" (R_(1))/(R_(2)) = (1)/(2)` Substitute the value of `M_(1), M_(2), R_(1) "and" R_(2)` and find the ratio of `(V_(e1))/(V_(e2))` `1 : sqrt(2)` |
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| 1614. |
Escape velocity on a planet is ve. If radius of the planet remains same and mass becomes 4 times, the escape velocity becomes(A) 4ve(B) 2ve(C) ve(D) 0.5 ve |
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Answer» Correct option is: (B) \(2v_e\) Escape Velocity \(v_e = \sqrt {2gRe}\) \(\frac{V_{e1}}{V_{e2}} \propto \sqrt \frac{4R_1}{R_1}\) \(V_{escape \ 2} = 2 \ V_{escape \ 1}\) Correct option is: (B) 2ve |
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| 1615. |
Escape velocity on a planet is e v . If radius of the planet remains same and mass becomes 4 times, the escape velocity becomesA. Be doubledB. Be halvedC. Be tripledD. Not change |
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Answer» Correct Answer - D |
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| 1616. |
Two satellites A and B move round the earth in the same orbit. The mass of B is twice the mass of A.A. speeds of A and B are equalB. the potential energy of A and B are equalC. the kinetic energy of A and B are equalD. the total energy of A is same as that of B |
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Answer» Correct Answer - a Since speed is independent of mass. |
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| 1617. |
There are two planets. The ratio of radius of two planets is `k` but ratio of acceleration due to gravity of both planets is g. What will be the ratio of their escape velocity ?A. ` (Kg)^(1//2)`B. `(Kg)^(-1//2)`C. `(Kg)^(2)`D. `(Kg)^(-2)` |
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Answer» Correct Answer - A `v = sqrt(2gR)` `:. (v_(1))/(v_(2)) = sqrt((g_(1))/(g_(2))xx (R_(1))/(R_(2))) = sqrt(g xx k) = (Kg)^(1//2)` |
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| 1618. |
When a body is freely suspended, the weight is evidenced by …………… A) gravitational force B) normal forceC) tension D) none of these |
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Answer» Correct option is C) tension |
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| 1619. |
The time period of a satellite depends on the …………………. of the planet. A) diameter B) radius C) mass of satellite D) both A & B |
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Answer» D) both A & B |
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| 1620. |
What is the difference between mass and weight of an object? Will the mass and weight of an object on the earth be the same as their values on Mars? Why? |
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Answer» The mass of an object is the amount of matter present in it. It is same everywhere in the Universe and is never zero. It is a scalar quantity and its SI unit is kg. The weight of an object is the force with which the earth (or any other planet/ moon/star) attracts it. It is directed towards the centre of the earth. The weight of an object is different at different places on the earth. It is zero at the earth’s centre. It is a vector quantity and its SI unit is the newton (N). The magnitude of weight = mg. The mass of an object will be the same on the earth and Mars, but the weight will not be the same because the value of g on Mars is different from that on the earth. |
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| 1621. |
There is no effect of rotational motion of earth on the value of g atA. PolesB. EquatorC. `45^(@)` latitudesD. All of these |
| Answer» Correct Answer - A | |
| 1622. |
If G is universal gravitational constant and g is acceleration due to gravity then the unit of the quantity `(G)/(g)` isA. `kg//m^(2)`B. `m^(2)//kg`C. kg/mD. m/kg |
| Answer» Correct Answer - B | |
| 1623. |
If G is universal gravitational constant and g is acceleration due to gravity then the unit of the quantity `(G)/(g)` isA. `"km-m"^(2)`B. `"kgm"^(-1)`C. `"kgm"^(-2)`D. `"m"^(2) "kg"^(-1)` |
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Answer» Correct Answer - D `g=(GM)/(R^(2))or(G)/(g)=(R^(2))/(m)` `:. (G)/(g)` will have the units `(m^(2))/(kg)` |
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| 1624. |
You can shield a charge from electrical forces by putting it inside a hollow conductor. Can you shield a body from the gravitational influence of nearby matter by putting it inside a hollow sphere or by some other means? |
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Answer» No Gravitational influence of matter on nearby objects cannot be screened by any means. This is because gravitational force unlike electrical forces is independent of the nature of the material medium. Also, it is independent of the status of other objects. |
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| 1625. |
There have been suggestions that the value of the gravitational constant G becomes smaller when considered over very large time period (in billions of years) in the future. If that happens, for our earth, (a) nothing will change. (b) we will become hotter after billions of years. (c) we will be going around but not strictly in closed orbits. (d) after sufficiently long time we will leave the solar system. |
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Answer» (c) we will be going around but not strictly in closed orbits. (d) after sufficiently long time we will leave the solar system. |
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| 1626. |
Which of the following are true?(a) A polar satellite goes around the earth’s pole in northsouth direction. (b) A geostationary satellite goes around the earth in east-west direction. (c) A geostationary satellite goes around the earth in west-east direction. (d) A polar satellite goes around the earth in east-west direction. |
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Answer» (a) A polar satellite goes around the earth’s pole in northsouth direction. (c) A geostationary satellite goes around the earth in west-east direction. |
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| 1627. |
Supposing Newton’s law of gravitation for gravitation forces F1 and F2 between two masses m1 and m2 at positions r1 and r2 read F1 = -F2 = -(r12/r123)GMo2(m1m2/Mo2)n where M0 is a constant of dimension of mass, r12 = r1 – r2 and n is a number. In such a case,(a) the acceleration due to gravity on earth will be different for different objects.(b) none of the three laws of Kepler will be valid.(c) only the third law will become invalid.(d) for n negative, an object lighter than water will sink in water. |
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Answer» (a) the acceleration due to gravity on earth will be different for different objects. (c) only the third law will become invalid. (d) for n negative, an object lighter than water will sink in water. |
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| 1628. |
Centripetal acceleration ………A) \(\cfrac{v}r\)B) \(\cfrac{v^2}r\)C) \(\cfrac{v^2}{r^2}\)D) \(\cfrac{v}{r^3}\) |
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Answer» B) \(\cfrac{v^2}r\) |
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| 1629. |
Centripetal force ………A) \(\cfrac{mv}R\)B) \(\cfrac{mv^2}{R^3}\)C) \(\cfrac{mv^2}{R}\)D) \(\cfrac{m^2v}{R}\) |
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Answer» C) \(\cfrac{mv^2}{R}\) |
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| 1630. |
Time period of a body moving around a body of radius R, with velocity v is ……………A) T = \(\cfrac{2πR}v\)B) T = \(\cfrac{v}{2πR}\)C) T = \(\cfrac{2πv}R\)D) T= \(\cfrac1{2πRv}\) |
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Answer» A) T = \(\cfrac{2πR}v\) |
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| 1631. |
Which of the following statements about the gravitational constant is true?(A) It has no units. (B) It has same value in all systems of units. (C) It is a force. (D) It does not depend upon the nature of medium in which the bodies lie. |
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Answer» (D) It does not depend upon the nature of medium in which the bodies lie. |
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| 1632. |
The gravitational force between two bodies is ______ (A) attractive at large distance only (B) attractive at small distance only (C) repulsive at small distance only (D) attractive at all distances large or small |
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Answer» (D) attractive at all distances large or small |
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| 1633. |
Mass of a particle at the centre of the Earth is (A) infinite. (B) zero. (C) same as at other places. (D) greater than at the poles. |
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Answer» Correct option is: (C) same as at other places |
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| 1634. |
Which of the following is not a property of gravitational force?(A) It is an attractive force. (B) It acts along the line joining the two bodies. (C) The forces exerted by two bodies on each other form an action-reaction pair. (D) It has a very finite range of action. |
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Answer» (D) It has a very finite range of action. |
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| 1635. |
If the distance between Sun and Earth is made two third times of the present value, then gravitational force between them will become(A) 4/9 times(B) 2/3 times(C) 1/3 times(D) 9/4 times |
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Answer» Correct option is: (D) \(\frac{9}{4}\) times Gravitational Force \(F = \frac{G \ m_1m_2}{r^2}\) \(\frac{F_2}{F_1} = \left(\frac{r_1}{r_2}\right)^2\) \(\frac{F_2}{F_1} = \left(\frac{r_1}{\frac{2}{3}r_1}\right)^2\) \(\frac{F_2}{F_1} = \frac{9}{4}\) \(\implies F_2 = \frac{9}{4} \ F_1\) Correct option is: (D) \(\frac{9}{4}\) times |
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| 1636. |
Acceleration due to gravity above the Earth’s surface at a height equal to the radius of the Earth is ______(A) 2.5 m/s2(B) 5 m/s2(C) 9.8 m/s2(D) 10 m/s2 |
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Answer» Correct option is: (A) 2.5 m/s2 |
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| 1637. |
A particle of mass 10-6 kg performs uniform circular motion. Its period is 10 s and the radius of the circle is 2 m. Find (i) the speed of the particle (ii) the centripetal acceleration of the particle (iii) the centripetal force on the particle. |
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Answer» (i) 1.257 m/s (ii) 0.79 m/s2 (iii) 7.9 × 10-7 N |
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| 1638. |
Distinguish between mass and weight |
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Answer»
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| 1639. |
What is a parking orbit? |
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Answer» The orbit of a geostationary satellite is called a parking orbit. |
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| 1640. |
A satellite going round the earth in a circular orbit loses some energy due to a collision. Its speed is `upsilon` and distance from the earth is d.A. Velocity increases and distance decreasesB. Both velocity and distance increaseC. Both velocity and distance decreaseD. Velocity decreases and distance increases |
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Answer» Correct Answer - A |
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| 1641. |
Calculate the velocity with which a body must be thrown vertically upward from the surface of the earth so that it may reach a height of `10R`, where `R` is the radius of the earth and is equal to `6.4 xx 10^(6)m.` (Given: Mass of the earth `= 6 xx 10^(24) kg`, gravitational constant `G = 6.7 xx 10^(-11) N m^(2) kg^(-2)`) |
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Answer» Correct Answer - `1.07xx10^(4)ms^(-1)` Conservation of energy gives `1/2mv^(2)-(GMm)/R=0-(GMm)/((R+10R))` `v=sqrt((20/11(Gm)/R)=1.07xx10^(4)ms^(-1)` |
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| 1642. |
A satellite of mass m revolves around the earth of radius R at a hight x from its surface. If g is the acceleration due to gravity on the surface of the earth, the orbital speed of the satellite isA. `(gR^2)/(R+x)`B. `(gR)/(R -x)`C. gxD. `((gR^2)/(R +x))^(1//2)` |
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Answer» Correct Answer - D (d) Gravitational force provides the necessary centripetal force. `(mv^2)/((R+x)) = (GmM)/((R + x)^2) also g = (GM)/(R^2)` `:.v^2 = (gR^2)/(R +x) rArr v = ((gR^2)/(R + x))^(1//2)` |
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| 1643. |
The escape velocity for a body projected vertically upwards from the surface of earth is 11km/s. If the body is projected at an angle of `45^@` with the vertical, the escape velocity will beA. `11sqrt2km/s`B. 22km/sC. 11km/sD. `(11)/(sqrt2) km/s` |
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Answer» Correct Answer - C (c ) `V_e = sqrt(2gR)` The escape velocity is independent of the angle at which the body is projected. |
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| 1644. |
If the distance between the earth and the sun were half its present value, the number of days in a year would have beenA. 64.5B. 129C. 182.5D. 730 |
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Answer» Correct Answer - B |
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| 1645. |
Assertion: if an earth satellite moves to a lower orbit, there is some dissipation of energy but the satellite speed increases. Reason: The speed of satellite is a constant quantity.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - C |
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| 1646. |
Assertion : Earth has an atmosphere but the moon does not. Reason : Moon is very small in comparison to earth.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - B |
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| 1647. |
Assertion: The time period of geostationary satellite is `24` hrs. Reason: Geostationary satellite must have the same time period as the time taken by the earth to complete on revolution about its axis.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If the assertion and reason both are false. |
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Answer» Correct Answer - B |
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| 1648. |
Statement-1:The escape speed of a body of mass `m` is `v_(e)`. The escape speed of another body of mass `2m` for same planet is `v_(e)`. Statement-2: The escape speed of a body for a given planet is independent of mass of body.A. Statement-1 is true, statement-2 is true, Statement-2 is a correct explanation for statement-1.B. Statement-1 is true, Statement-2 is true, statement-2 is Not a correct explanation for statement-1C. Statement-1 is true, Statement-2 is false.D. Statement-1 is false Statement-2 is True. |
| Answer» Correct Answer - a | |
| 1649. |
The escape Velocity from the earth is `11.2 Km//s`. The escape Velocity from a planet having twice the radius and the same mean density as the earth, is :A. `11.2 km//s`B. `15.00 km//s`C. `22.4 km//s`D. `5.8 km//s` |
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Answer» Correct Answer - C Escape velocity, `v_(e)=sqrt((2GM_(E))/(R_(E)))` Also since earth is assumed spherical in shape its mass is given by `M=4/3 pi R^(3)xxrho` `:. v_(e)=sqrt((2G)/Rxx4/3piR^(3)rho)=Rsqrt(8/3 pi G rho)` ` :. v_(e) prop R` if `rho`=constant Since the planet having double radius in comparison to earth, therefore the escape velocity becomes twice, i.e. `22km//s ` |
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| 1650. |
The difference in the lengths of a mean solar day and a sidereal day is aboutA. `4 mi n`B. `1 mi n`C. `15 mi n`D. `56 mi n` |
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Answer» Correct Answer - A Sideral day is about `4` min shorter than our normal solar `24` h day. It is abour `3` min `56s`. |
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