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Assertion (A) : LASER is used to measure...

Assertion (A) : LASER is used to measure distant object as moon.
Reason (R) : They are highly coherent source of light.

A

Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'.

B

Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'

C

'A' is true and 'R' is false

D

'A' is false and 'R' is true

Text Solution

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The correct Answer is:
A
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AAKASH SERIES-ATOMS-EXERCISE -IB
  1. When an electron of the hydrogen atom jumps from a higher to lower en...

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  2. (A) hydrogen atom consists of only one electron but its emission spect...

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  3. (A) for the scattering of alpha- particles at large angles, only the n...

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  4. Statement-1 : Between any two given energy levels, the number of abosr...

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  5. (A) atoms of each element are stable and emit characteristic spectrum....

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  6. (A) most of the mass of the atom is concentrated in its nucleus. (R)...

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  7. (A) bohr's third postulaate states that the stationary orbits are thos...

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  8. (A) the total energy of an electron revolving in any stationary orbit ...

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  9. (A) in the experiment of alpha particle scattering, extremely thin gol...

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  10. (A) in alpha particle scattering number of alpha paritcle undergoing h...

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  11. (A) electrons int the atom are held due to coulomb forces. (R) the a...

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  12. (A) according to classical electromagnetic theory an accelerated parti...

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  13. Assertion : A laser beam of 0.2 watt power can drill holes through a m...

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  14. Assertion (A) : LASER is used to measure distant object as moon. Re...

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  15. Assertion In He-Nelaser, population inversion takes place between ener...

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  16. Assertion : Crystalline solids can cause Xrays to diffract. Reason...

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  17. A: In beta-decay an electron is emitted by the nucleus R: Electrons ...

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  18. Assertion : X-ray astronomy is possible only from satellites orbiting ...

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  19. According to Bohr's atomic model

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  20. Assertion : Total energy of electron in an hydrogen atom is negative. ...

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