1
JEE Main 2020 (Online) 2nd September Evening Slot
+4
-1
The height ‘h’ at which the weight of a body will be the same as that at the same depth ‘h’ from the surface of the earth is (Radius of the earth is R and effect of the rotation of the earth is neglected)
A
$${R \over 2}$$
B
$${{\sqrt 5 R - R} \over 2}$$
C
$${{\sqrt 3 R - R} \over 2}$$
D
$${{\sqrt 5 } \over 2}R - R$$
2
JEE Main 2020 (Online) 2nd September Morning Slot
+4
-1
The mass density of a spherical galaxy varies as $${K \over r}$$ over a large distance ‘r’ from its centre. In that region, a small star is in a circular orbit of radius R. Then the period of revolution, T depends on R as :
A
T2 $$\propto$$ R
B
T2 $$\propto$$ R3
C
T $$\propto$$ R
D
T2 $$\propto$$ $${1 \over {{R^3}}}$$
3
JEE Main 2020 (Online) 9th January Evening Slot
+4
-1
Planet A has mass M and radius R. Planet B has half the mass and half the radius of Planet A. If the escape velocities from the Planets A and B are vA and vB, respectively, then $${{{v_A}} \over {{v_B}}} = {n \over 4}$$. The value of n is :
A
1
B
2
C
4
D
3
4
JEE Main 2020 (Online) 9th January Morning Slot
+4
-1
A body A of mass m is moving in a circular orbit of radius R about a planet. Another body B of mass $${m \over 2}$$ collides with A with a velocity which is half $$\left( {{{\overrightarrow v } \over 2}} \right)$$ the instantaneous velocity$${\overrightarrow v }$$ of A. The collision is completely inelastic. Then, the combined body :
A
starts moving in an elliptical orbit around the planet.
B
Falls vertically downwards towards the planet
C
Escapes from the Planet's Gravitational field.
D
continues to move in a circular orbit
JEE Main Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
Coordinate Geometry
Calculus
EXAM MAP
Joint Entrance Examination