Download App

STD 11 - 7. gravitation — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 11 - 7. gravitation4 Marks
MCQ
An artificial satellite is moving around earth in a circular orbit with speed equal to one fourth the escape speed of a body from the surface of earth. The height of satellite above earth's surface is ............ ($R$ is radius of earth)
  • A
    $3 R$
  • B
    $5 R$
  • ✓
    $7 R$
  • D
    $8 R$
✓

Answer

Correct option: C.
$7 R$
c
(c)

Escape velocity $=\sqrt{2 gR }$

Speed of satellite $=\frac{\sqrt{2 g R}}{4}$

By force balance,

$\frac{ GMm }{ x ^2}=\frac{ m \left(\frac{\sqrt{2 gR }}{4}\right)^2}{ x }$

$x =\frac{ GM }{2 gR } \times 16=8 \frac{ GM }{ gR }=8 R$

Height of satellite above earth's surface is $8 R-R=7 R$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

JEE STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

In the circuit shown in figure, if both the bulbs $B_1$ and $B_2$ are identical then
→
There are two planets. The ratio of radius of the 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
→
Which of the following statement is $NOT$ correct ?
→
In a diffraction pattern due to a single slit of width $a$, the first minimum is observed at an angle $30^o $ when light of wavelength $5000 \;\mathring A$ is incident on the slit. The first secondary maximum is observed at an angle of
→
If the radius of curvature of the path of two particles of same masses are in the ratio $1 : 2$, then in order to have constant centripetal force, their velocity, should be in the ratio of
→
The acceleration of system of two bodies over the wedge as shown in the figure is ....... $m/sec^2$
→
The same retarding force is applied to stop a train. The train stops after $80\, m$. If the speed is doubled, then the stopping distance will be
→
The engine of a train moving with speed $10\,ms ^{-1}$ towards a platform sounds a whistle at frequency $400\,Hz$. The frequency heard by a passenger inside the train is $........\,Hz$ (neglect air speed. Speed of sound in air $330\,ms ^{-1}$ )
→
A wire of cross section $4 \;mm^2$ is stretched by $0.1\, mm$ by a certain weight. How far (length) will be wire of same material and length but of area $8 \;mm^2$ stretch under the action of same force......... $mm$
→
A particle covers $50\, m$ distance when projected with an initial speed. On the same surface it will cover a distance, when projected with double the initial speed ......... $m$
→