Tag: gravitation

Questions Related to gravitation

what is mass of the moon?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. $6 \times {10^{24}}$ kg

  2. $7.4 \times {10^{22}}$ kg

  3. $6 \times {10^{22}}$ kg

  4. $7.4 \times {10^{24}}$ kg

Show answer
Correct Option: B
Explanation:

The mass of the moon is $7.4\times 10^{22}kg.$

The correct option is B.

Following factors may be responsible for the colour of a star.
I. The size of the star
II. The distance of the star from the earth
III. The surface temperature of the star
Which combination is correct?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. III only

  2. II only

  3. I and II only

  4. I, II and III

Show answer
Correct Option: C
Explanation:

Factor responsible for colour of the star is surface temperature of the star it does not depend upon size of the star and distance of star from the earth.

Who is known as father of Modern Indian Astronomy?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Venkoji Bapu Ketkar

  2. Meghnath Saha

  3. M.K. Vainu Bappu

  4. Dr. S. Chandrashekhar

Show answer
Correct Option: C
Explanation:

Manali Kallat Vainu Bappu or M.K Vainu Bappu is known the father of Modern Indian Astronomy. He along with American astronomer Olin Chaddock Wilson discovered the Wilson-Bapu effect in 1957.  

Thus, the correct answer is 'M.K. Vainu Bappu.'

Suppose an earth satellite, revolving in a circular orbit experiences a resistance due to cosmic dust. Then.

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Its kinetic energy will increase

  2. Its potential energy will decrease

  3. It will spiral towards the earth and in the process its angular momentum will remain conserved

  4. Both a and b is correct

Show answer
Correct Option: D
Explanation:
The Kinetic energy of the satellite increases in spiral path as it approach the earth so $V$ must increase the total mechanical energy of the satellite decreases due to resistance from conic dust as satellite approaches earth so potential energy decreases.
Thus Kinetic energy increase potential energy decreases.

The Halley's comet appears after every

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. $72$ years

  2. $74$ years

  3. $75$ years

  4. $78$ years

Show answer
Correct Option: C
Explanation:

Halley's comet appears after every  $75$ years.

Halley's Comet is arguably the most famous comet. It is a "periodic" comet and returns to Earth's vicinity about every $75$ years, making it possible for a human to see it twice in his or her lifetime. The last time it was here was in 1986, and it is projected to return in $2061.$

The comet is named after English astronomer Edmond Halley, who examined reports of a comet approaching Earth in $1531, 1607$ and $1682$. He concluded that these three comets were actually the same comet returning over and over again, and predicted the comet would come again in $1758$.

Which is the brightest star visible from earth?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. Sirius

  2. Antares

  3. Vega

  4. Rigel

Show answer
Correct Option: A
Explanation:

The brightest strain the shy is Sirius also known as Dog star or more officially Alpha can is Magon's for its position in constellation canis Major.

What is metrology?

physics gravitation elementary ideas of astronomy shadow formation and optical medium light and shadow

  1. The study of people's influx to a metropolitan city

  2. The study of earth's atmosphere

  3. The science of measuring

  4. The study of meteors

Show answer
Correct Option: C
Explanation:

Metrology is the scientific study of the atmosphere that focuseson weather processes and forecasting.

Each day how many high and low tides are there?

physics gravitation tides movements of ocean and sea water circulation of ocean water

  1. 2 high tides and 2 low tides

  2. 1 high tide and 2 low tides

  3. 2 high tides and 1 low tide

  4. 1 high tide and 1 low tide

Show answer
Correct Option: A
Explanation:

2 low tides and 2 high tides are experienced every lunar day, 

i.e., 24 hours and 50 minutes.

What are known as Spring Tides?

physics gravitation tides movements of ocean and sea water circulation of ocean water

  1. When sun and moon are aligned causes strong high and low tides

  2. When sun and moon are not aligned causes strong high and low tides

  3. When sun and moon are aligned causes only low tides

  4. When sun and moon are not aligned causes only high tides

Show answer
Correct Option: A
Explanation:

Tide with the greatest difference between the high and low tide, 

that occurs just after a new or full moon is a spring tide.

A stone drop from height 'h' reaches at earth surface in 1 sec. If the some stone taken to moon and drop freely from height h then it will reaches at the surface of moon in the time:

physics gravitation tides movements of ocean and sea water circulation of ocean water

  1. $\sqrt { 6 } sec$

  2. 9 sec

  3. $\sqrt { 3 } sec$

  4. 6 sec

Show answer
Correct Option: A