A particle 'A' moving with a certain velocity has the de-Broglie

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 Multiple Choice QuestionsMultiple Choice Questions

171.

A proton is converted to a neutron by

1.β- emission

2.β+ emission

3. electron capture

Which of the statements given above are correct?

  • (1) and (2) only 

  • (2) and (3) only

  • (1) and (3) only

  • (1), (2) and (3)


172.

In Neptunium series

Pu94241AmNpPaU92238, the order of radiation

  • β,α,α,β

  • β,β,α,α

  • α,α,β,β

  • α,β,α,β


173.

What number of subshells are possible in n = 3 energy level?

  • 7

  • 8

  • 9

  • 6


174.

Four different sets of quantum numbers for 4 electrons are given below:

e1 = 4, 0, 0, -12

e2 = 3, 1, 1, -12

e3 = 3, 2, 2, +12

e4 = 3, 0, 0, +12

The order of energy of e1, e2, e3, e4 is 

  • e> e> e> e4

  • e> e> e> e1

  • e> e> e> e4

  • e> e> e> e1


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175.

Which of the following nuclei is most unstable?

  • Ca2040

  • Mn3555

  • Sn50119

  • Al1330


176.

Electron affinity is positive when

  • O- is formed from O

  • O2- is formed from O-

  • O+ is formed from O

  • electron affinite is always a negative value


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177.

A particle 'A' moving with a certain velocity has the de-Broglie wavelength 1 Å. For a particle 'B' with mass 25% of 'A' and velocity 75% of 'A'. The de-Broglie wave length of 'B' will be

  • 3 Å

  • 5.33 Å

  • 6.88 Å

  • 0.68 Å


B.

5.33 Å

By de-Broglie equation

        λA = hmAVAand λB = hmBvB  λAλB = mAVAmBvB           ...(i)

As mB = 25% of mass A

 mA = 1

and mB = 0.25

similarly, vB = 75% of velocity of A

 vA = 1 and vB = 0.75

By putting the values in equation (i)

λAλB = 0.25 mA × 0.75 vAmA × vAλAλB = 0.1875λB = λA0.1875 = 5.33 Å


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178.

The ratio of de-Broglie wavelengths for electron accelerated through 200 V and 50 V is

  • 1:2

  • 2:1

  • 3:10

  • 10:3


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179.

The nuclear reaction, Al1327 + He24  Si1430 + H11 is

  • nuclear fusion

  • nuclear fission

  • nuclear transmutation

  • artificial radioactivity


180.

n/p ratio during positron decay

  • increases

  • decreases

  • remains constant

  • All of these


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