JEE Main Physics Gravitation Online Test – JEE Main Online Test 2019

Figure shows the variation of energy with the orbit radius r of a satellite in a circular motion. Mark the correct statement.

A planet revolving around sun in an elliptical orbit has a constant

Both earth and moon are subject to the gravitational force of the sun. As observed from the sun, the orbit of the moon

Three particles each having a mass of 100 g are placed on the vertices of an equilateral triangle of side 20 cm. The work done in increasing the side of this triangle to 40 cm is

Two satellites S₁ & S₂ of equal masses revolve in the same sense around a heavy planet in coplanar circular orbit of radii R & 4R

Two identical spherical masses are kept at some distance as shown. Potential energy when a mass m is taken from surface of one sphere to the other

If W₁, W₂ and W₃ represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in a gravitational field of point mass m then

Maximum height reached by a rocket fired with a speed equal to 50% of the escape velocity from earth’s surface is:

A thin spherical shell of mass M and radius R has a small hole. A particle of mass m is released at the mouth of the hole. Then

A satellite in a circular orbit of radius r has time period of 4 hrs. A satellite with orbital radius of 4r around the same planet will have a time period of:

A particle of mass M is at a distance a from the surface of a thin spherical shell of equal mass and having radius a.

A solid sphere of uniform density and radius R applies a gravitational force of attraction equal to F₁ on a particle placed at a distance 3R from the centre of the sphere. A spherical cavity of radius R/2 is now made in the sphere as shown in the figure. The sphere with cavity now applies a gravitational force F₂ on the same particle. The ratio F₂/F₁ is

If the distance between the earth And the sun were half its present value the number of days in a year would have been

A satellite orbits the earth at a height of 400 km above the surface. How much energy must be expended to rocket the satellite out of the earth’s gravitational influence? Mass of the satellite = 200 kg, mass of the earth = 6.0 × 10²⁴ kg, radius of the earth = 6.4 × 10⁶ m, G = 6.67 × 10^-11 N-m²/kg².

A particle of mass m is moved from A to B as shown in figure. Then potential energy of the particle

A satellite is in a circular orbit around the earth has kinetic energy E_k. Minimum amount of energy that is added so that it escapes the earth’s gravitational field is:

Assertion From a solid sphere of radius R, a hole of radius R/2 is cut as shown in figure. To find the magnitude of gravitational potential and gravitational field strength at O, we can directly subtract Potential due to hole (before removing) from potential due to whole sphere (before removing). The same can be done to find field strength at O, although potential is a scalar quantity and field strength is a vector quantity.

Reason In gravity, it is done like this. It makes no difference, whether the field strength is added/subtracted by vector method or by scalar method.

At a distance 320 km above the surface of earth, the value of acceleration due to gravity will be lower than its value on the surface of the earth by nearly (radius of earth = 6400 km)

Assertion A planet may orbit around a star either in orbit P or orbit Q. The speed of planet at O is same for both orbits.

Reason Planets orbit around a star with uniform velocity.

If the distance between the earth and the sun were half its present value, the number of days in a year would have been