An object of mass $$m$$ is located on the surface of a spherical planet of mass $$M$$ and radius $$R$$. The escape speed from the planet does not depend on which of the following?

the acceleration due to gravity on that planet

MCQ Questions for Class 11 Engineering Physics Gravitation Quiz 16

The work done by external agent to shift a point mass from infinity to the centre of earth is :

0%
$=0$
0%
$>0$
0%
$<0$
0%
$<0$

Explanation

Work done by external agent is

W = m (d V)

$W= m(dV)$

d V =

$dV=$ change in potential energy.

So,

W = m (V_{2} - V_{1})

$W= m(V_2- V_1)$ .....(i)

At infinity

V_{1} = 0

$V_1= 0$

On the center of earth ,

V_{2} = \frac{- 3 G M}{2 R}

$V_2= \dfrac{-3GM}{2R}$ ...(ii)

Putting (i) equation in equation (ii) we get,

W = m \frac{- 3 G M}{2 R}

$W= m\dfrac{-3GM}{2R}$

W = \frac{- 3 G M m}{2 R}

$W= \dfrac{-3GMm}{2R}$

This shows that work done cannot be zero.

Here, Work done is negative

which results in

W < 0

$W<0$

Option (C) is correct.

A body is thrown from the surface of the earth with a speed of

\sqrt{G M / R} (R =

$\sqrt {GM/R} (R =$ radius and

M =

$M =$ mass of earth). It rises to a maximum height of

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$R/2$
0%
$R$
0%
$4R$
0%
$2R$

A capillary tube is immersed vertically in water and the height of the water column is X. When this arrangement is taken into a mine of depth d, the height of the water column is Y. If R is the radius of the earth, the ratio X/Y is

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$1-\dfrac{d}{R}$
0%
$1$ + $\dfrac{d}{R}$
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$\dfrac{R-d}{R+d}$
0%
$\dfrac{R+d}{R-d}$

The escape velocity of a body on the surface of the earth is

11.2 k m / s e c

$11.2\ km/sec$ . If the mass and radius of a planet are

4

$4$ and

2

$2$ times respectively than that of earth. The escape velocity from the planet will be :

0%
$11.2\ km/sec$
0%
$1.112\ km/sec$
0%
$15.8\ km/sec$
0%
$22.4\ km/sec$

The gravitational force in a region is given by

\to E = a y^i + a x^j

$\vec{E}=ay\hat i+ax \hat j$
The work done by gravitational force to shift a point mass

m

$m$ from

(0, 0, 0)

$(0, 0, 0)$ to

(x_{0}, y_{0}, z_{0})

$(x_0, y_0, z_0)$ is :

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$ma\ x_0y_0z_0$
0%
$ma\ x_0y_0$
0%
$-ma\ x_0y_0$
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$zero$

The gravitational field in a region is

10 N / k g (^i -^j)

$10\ N/kg (\hat i -\hat j)$ . The work done by external agent to shift slowly a particle of mass

1 k g

$1\ kg$ from point

(1 m, 1 m)

$(1\ m, 1\ m)$ to a point

(2 m, - 2 m)

$(2\ m, -2\ m)$ is :

0%
$40\ joule$
0%
$-40\ joule$
0%
$zero$
0%
$+10\ joule$

A body is projected vertically from the surface of the earth of radius

R

$R$ with velocity equal to half of the escape velocity. The maximum height reached by the body is?

0%
$R/5$
0%
$R/3$
0%
$R/2$
0%
$R/4$

Two bodies each of mass

1 k g

$1\ kg$ are at a distance of

1 m

$1\ m$ . The escape velocity of a body of mass

1 k g

$1\ kg$ which is midway between them is :

0%
$8\times 10^{-5}\ m/s$
0%
$2.31\times 10^{-5}\ m/s$
0%
$4.2\times 10^{-5}\ m/s$
0%
$zero$

A gravitational field is present in a region. A point mass is shifted from

A

$A$ to

B

$B$ , from different paths shown in the figure. If

W_{1}, W_{2}

$W_1, W_2$ and

W_{3}

$W_3$ represent work done by gravitational force for respective paths, then :

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$W_1=W_2=W_3$
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$W_1>W_2W_3$
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$W_1>W_3>W_2$
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none of these

During the compression of the spring the work done by the force of gravity is

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$Mgx$
0%
$\left(\dfrac {1}{2}\right)kx^2$
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$-\left(\dfrac {1}{2}\right)kx^2$
0%
$Mgx + \left(\dfrac {1}{2}\right)kx^2$

Acceleration due to gravity 'g' for a body of mass 'm' on earth's surface is proportional to (Radius of earth= R , mass of earth= M)

0%
$GM/R^2$
0%
$m^0$
0%
$mM$
0%
$1/R^{3/2}$

An object of mass

m

$m$ is located on the surface of a spherical planet of mass

M

$M$ and radius

R

$R$ . The escape speed from the planet does not depend on which of the following?

0%
$M$
0%
$m$
0%
the density of the planet
0%
$R$
0%
the acceleration due to gravity on that planet

CBSE Questions for Class 11 Engineering Physics Gravitation Quiz 16 - MCQExams.com

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Practice Class 11 Engineering Physics Quiz Questions and Answers

CBSE Questions for Class 11 Engineering Physics Gravitation Quiz 16 - MCQExams.com

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Practice Class 11 Engineering Physics Quiz Questions and Answers

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