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 :

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

Explanation

Work done by external agent is

$W= m(dV)$

$dV=$ change in potential energy.

So,

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

At infinity

$V_1= 0$

On the center of earth ,

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

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

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

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

This shows that work done cannot be zero.

Here, Work done is negative

which results in

$W<0$

Option (C) is correct.

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

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

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

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$R/2$
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$R$
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$4R$
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$2R$

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

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

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

$4$ and

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

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

The gravitational force in a region is given by

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

$m$ from

$(0, 0, 0)$ to

$(x_0, y_0, z_0)$ is :

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$ma\ x_0y_0z_0$
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$ma\ x_0y_0$
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$-ma\ x_0y_0$
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$zero$

The gravitational field in a region is

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

$1\ kg$ from point

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

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

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

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

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

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$R/5$
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$R/3$
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$R/2$
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$R/4$

Two bodies each of mass

$1\ kg$ are at a distance of

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

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

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

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

$A$ to

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

$W_1, W_2$ and

$W_3$ 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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$Mgx$
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$\left(\dfrac {1}{2}\right)kx^2$
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$-\left(\dfrac {1}{2}\right)kx^2$
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$Mgx + \left(\dfrac {1}{2}\right)kx^2$

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)

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

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?

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$M$
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$m$
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the density of the planet
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$R$
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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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