 ## Physics Class 11 - Chapter 8 question 1 to 4

Q8.1 (a) 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 ?
(b) An astronaut inside a small space ship orbiting around the earth cannot detect
gravity. If the space station orbiting around the earth has a large size, can he hope
to detect gravity ?
(c) 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 greater than the moon’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 sun.Why ?

Ans: Q8.2Choose the correct alternative :
(a) Acceleration due to gravity increases/decreases with increasing altitude.
(b) Acceleration due to gravity increases/decreases with increasing depth (assume
the earth to be a sphere of uniform density).
(c) Acceleration due to gravity is independent of mass of the earth/mass of the body.
(d) The formula –G Mm(1/r2 – 1/r1) is more/less accurate than the formula
mg(r2 – r1) for the difference of potential energy between two points r2 and r1 distance
away from the centre of the earth.

Ans: Q8.3Suppose there existed a planet that went around the sun twice as fast as the earth.
What would be its orbital size as compared to that of the earth ?

Ans:  Q8.4 if, one of the satellites of Jupiter, has an orbital period of 1.769 days and the radius of the orbit is 4.22 × 108 m. Show that the mass of Jupiter is about one-thousandth that of the sun.

Ans:  