Important Questions Of Physics That Generally Ask In Exams #2

< _Today Que_ Why Atmosphere lies on Earth? >

<< Atmosphere lies on earth because of Earth's gravitational attraction >>

Earth’s atmosphere is an extremely thin skin surrounding our planet. What force keeps it from flying off into space.
Earth’s atmosphere is only 1/1,200,000 the mass of Earth itself. So it is a very thin skin surrounding our planet.

And yet, although you might not realize it or think about it, Earth does continually lose some of its atmosphere to space. This loss occurs in the upper atmosphere, over billion-year time scales.

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Molecules in our atmosphere are constantly moving, spurred on by energizing sunlight. Some move quickly enough to escape the grip of Earth’s gravity. The escape velocity for planet Earth is a little over 11 kilometers per second – about 25 thousand miles an hour. If Earth were much less massive – say, as massive as Mars – gravity’s grip would be weaker. That’s one reason why Mars lost most of its original atmosphere.

In the vicinity of our heavier Earth, where gravity is stronger than on Mars, not all particles are equally likely to escape. Light ones, like hydrogen and helium, typically move faster than heavier ones, like oxygen and nitrogen. The light atoms are more likely to reach escape velocity and escape to space. That’s why light molecules are rare in our atmosphere, in contrast to their abundance in the universe at large.

Here some important Questions of Physics are listed bellow …# 2

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1.Which gas is used in thermometer to measure very low temperature ?
=> Helium (HE)

2. Which thermometer is use to measure to the high temperature ?
=> Radiation Pyrometer (Pyrometer)


3. Who first derive the relationship between work and heat ?
=> Dr. Joule

4. How many joule of work is equal to 1 kilocalorie ?
=> 4.184X103 joule (4184)

5. For which colour the focal length of convex lens is maximum ?
=> Maximum is for Red light .

6. For which colour the focal length of convex lens is minimum ?
=> Minimum is for Voilet

7.Where is the largest reflecting telescope of the world is kept ?
=> Mount Palomer (california)

8. what is the Aperture of objective mirror of largest reflecting telescope ?
=> 3.0 metres (120 inch)

9. Candela is a unit of which Quantity ?
=>Luminous Intensity (lv)

10.How much Angstrom (Å ) wavelength does our eyes have?
=> 7000 Å

11. Sodium light consist of two wavelength , what are they ?
=> 5890 Å and 5896 Å

12. What is the angle between the plane of vibration and the plane of polarization of polarized light ?
=> 90°

13. Who was awarded by Nobel prize for the experiment of scattering of light ?
=> Sir C.V Raman

14. Which instrument is use to measure the intensity of earthquake ?
=> Seismograph


15.In which scale the intensity of earthquake is measure ?
=> Richter Scale and Mercalli Scale

16.By which force is the cream separated from milk when churned ?
=> Centrifugal Force.

17. Why the atmosphere is on the Earth ?
=> Due to of suitable Gravity

18. What are the constituents of earth atmosphere ?

=> nitrogen (78.1%) , oxygen (20.9%) , argon (0.9%), carbon dioxide (0.035%), water vapor, and some other gases.

19.By which element the filament of bulb is made ?
=> Tungsten

tungsten-filament of bulb
tungsten-filament of bulb

20. How many elctrons are there in one coulomb of charge ?
=> 6.25X1018

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