#### 11th Standard Physics Gravitation English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Physics

Time : 00:20:00 Hrs
Total Marks : 20

20 x 1 = 20
1. If the masses of the Earth and Sun suddenly double, the gravitational force between them will

(a)

remain the same

(b)

increase 2 times

(c)

increase 4 times

(d)

decrease 2 times

2. According to Kepler’s second law, the radial vector to a planet from the Sun sweeps out equal areas in equal intervals of time. This law is a consequence of

(a)

conservation of linear momentum

(b)

conservation of angular momentum

(c)

conservation of energy

(d)

conservation of kinetic energy

3. The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are KA, KB and KC respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then

(a)

KA > KB >KC

(b)

KB < KA < KC

(c)

KA < KB < KC

(d)

KB > KA > KC

4. If the mass and radius of the Earth are both doubled, then the acceleration due to gravity g'

(a)

remains same

(b)

${g\over 2}$

(c)

2g

(d)

4g

5. If a person moves from Chennai to Trichy, his weight

(a)

increases

(b)

decreases

(c)

remains same

(d)

increases and then decreases

6. If the acceleration due to gravity becomes 4 times its original value, then escape speed

(a)

remains same

(b)

2 times of original value

(c)

becomes halved

(d)

4 times of original value

7. In the following, what are the quantities which that are conserved?

(a)

Linear momentum of planet

(b)

Angular momentum of planet

(c)

Total energy of planet

(d)

Potential energy of a planet

8. A satellite is launched into a circular orbit of radius R around the earth. A second satellite is launched into an orbit of radius 4R. The ratio of their respective periods is _____________.

(a)

4:1

(b)

1:8

(c)

8:1

(d)

1:4

9. A body projected electrically from the earth reaches a height equal to earth's radius before returning to the earth: The power exerted by the gravitational force is greatest ____________.

(a)

at the highest position of the body

(b)

at the instant just before the body hits the earth

(c)

it remains constant all through

(d)

at the instant just after the body is projected

10. A body of mass 500g is town upwards with a velocity 20ms-1 and reaches back to the surface of a planet after 20s. Then the weight of the body on that planet is _____________.

(a)

2 N

(b)

4 N

(c)

5 N

(d)

1 N

11. Three bodies of each of mass 2 kg are situated on x-axis at distance 1m, 2m, 4m from origin. The resolving gravitational potential due to the system at the origin will be ______________.

(a)

2G

(b)

$\frac { 8 }{ 3 }$G

(c)

$\frac { 4 }{ 3 }$G

(d)

$\frac { 7 }{ 2 }$

12. If the acceleration due to gravity at the surface of the earth is g, the work done in slowly lifting a body of mass in from the earth's surface to a height R equal to the radius of the earth is ______________.

(a)

$\frac { 1 }{ 2 }$ MgR

(b)

2 MgR

(c)

$\frac { 1 }{ 4 }$ MgR

(d)

Mg R

13. Two spherical balls of mass 10hg are placed 10cm apart. Find gravitational force of attraction between them _______________.

(a)

the earth does not attract the objects in a satellite

(b)

the normal force by chair on the person balances the earth attraction

(c)

the normal force is zero

(d)

the person in sattelite is not accelerated

14. Which of following quantities remain constant in a planetary motion (consider elliptical orbits) as seen from the sun?

(a)

speed

(b)

angular momentum

(c)

kinetic energy

(d)

angular speed

15. A baker contacting a liquid is kept inside a big closed jar if the air inside the far is continuously pumped out, the pressure in the liquid near the bottom will________________.

(a)

increase

(b)

decrease

(c)

remain constant

(d)

first decrease and then increase

16. A solid is completely immersed in a liquid the force exerted by the liquid on the solid will ___________.

(a)

increase if it is P used deeper inside the liquid

(b)

change if its orientation is changed

(c)

increase if it is taken partially out of liquid

(d)

be in the vertically upward direction

17. The viscous force acting between 2 layers a liquid is given by$\frac { F }{ A } =\eta \frac { dv }{ dz }$=This F/A may be called

(a)

pressure

(b)

longitudinal stress

(c)

tangential stress

(d)

volume stress

18. A piece of wood is taken deep inside a long column of water & released it will move up.

(a)

with a constant upward acceleration

(b)

with decreasing upward acceleration

(c)

with a deceleration

(d)

there will be uniform velocity

19. According to Kepler, planet move in _____________.

(a)

Circular orbits around the Sun

(b)

Elliptical orbits around the Sun with Sun at exact centre

(c)

Straight lines with constant velocity

(d)

Elliptical orbits around the Sun with Sun at one of its foci

20. The period of revolution of planet A around the Sun is 8 times that of B. The distance of A from the Sun is how many times greater than that of B from the Sun ___________.

(a)

2

(b)

3

(c)

4

(d)

5