Gravitation class 11.....4 Flashcards
We can shield a charge from a electric fields by putting it inside a hollow conductor. can we shield a body from the gravitational influence of nearby matter by putting it inside a hollow sphere or by some other means ?
The gravitational forces are not depend upon the nature of the medium , but the electric force depends on the intervening medium between the charge and the charge and the electric field . So we cannot shield a body from the gravitational force.
An astronaut inside a small spaceship orbiting around the earth cannot detect gravity. If the space station orbiting around the earth has a large size, can be hope to detect gravity ?
Inside a small spaceship orbitting around the earth, the value of acceleration due to gravity g, can be considered as constant and hence astronaut feels weightlessness. In the space station orbitting around the earth has a large size, such that variation inmatters in the case astronaut inside the speceship will experience gravitational force and hence can detect gravity e.g., On the moon, due to larger size gravity can be detected.
If you compare the gravitational force on the earth due to the sun to that due to the moon , you would find that the Sun’s pull is grater than the moo’s pull, (you can check this yourself using the data available in the succeeding exercises ) . However , the tidal effect of the moon’ s pull is greater than the tidal effect of the sun . Why?
The tidal effect is inversely proportional to the cube of the distance while the gravitational force is inversely proportional to the square of the distance. Since the distance between sun and earth is much greater than that between the moon and earth , the effect observed due to the moon is more than due to the sun.
The elliptical orbits of planets were indicated by calculations of the orbit of which astronomical body?
Mars
If the eccentricities of the planetary orbits were taken as zero, then the sun is at the centre of the orbit.
a) True
b) False
T
the track wud become circular.
The gravitational constant is an empirical constant.
a) True
b) False
T
It is not derived
The value of gravitational constant was first determined by _____
a) Albert Einstein
b) Isaac Newton
c) Henry Cavendish
d) Stephen Hawking
c
What apparatus did Henry Cavendish use in his experiment to determine the gravitational constant?
1 bar, 2 small spheres and 2 large spheres
By measuring the torque and angle of deflection produced due to the proximity of large spheres to the small ones, Henry Cavendish was able to determine the universal gravitational constant.
What material were the spheres made up of in Henry Cavendish’s experiment?
a) Lead
b) Steel
c) Iron
d) Wood
a.
____ is a group of geostationary satellites sent up by India.
INSAT is a group of geostationary satellites sent up by India for telecommunications, broadcasting, meteorology, and search and rescue operations. Commissioned in 1983, INSAT is the largest domestic communication system in the Indo-Pacific Region.
Most waves used for communication purposes rely on geostationary satellites because ____
they cannot transmit data at long distances due to curvature of the earth.
However, they are not reflected by the ionosphere like radio waves and can be relayed to a wide area using geostationary satellites.
Polar satellites are used for high-resolution imaging of the earth’s surface because __
they are closer to the surface of the earth and can cover vast areas very quickly
How much is a polar orbit’s inclination with the earth’s equatorial plane?
90
