X-rays are emitted during from Chemistry Structure of Atom

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

631.

A metal surface is exposed to solar radiations :

  • the emitted electrons have energy less than a maximum value of energy depending upon frequency of incident radiations

  • the emitted electrons have energy less than maximum value of energy depending upon intensity of incident radiations

  • the emitted electrons have zero energy

  • the emitted electrons have energy equal to energy of photons of incident light


632.

Which of the following transitions have minimum wavelengths ?

  • n4  n1

  • n2  n1

  • n4  n2

  • n3  n1


633.

Orbital is :

  • circular path around the nucleus in which the electrons revolves

  • space around the nucleus where the probability of finding the electron is maximum

  • amplitude of electron wave

  • none of the above


634.

Which of the following sequence is correct as per Aufbau principle ?

  • 3s < 3d < 4s < 4p

  • ls < 2p < 4s < 3d

  • 2s < 5s < 4p < 5d

  • 2s < 5s < 4p < 5f


Advertisement
635.

A radioactive nucleus will not emit :

  • alpha and beta rays simultaneously

  • beta and gamma rays simultaneously

  • gamma and alpha rays

  • gamma rays only


Advertisement

636.

X-rays are emitted during

  • α, n reaction

  • K-capture

  • n, α-reaction

  • β- emission 


B.

K-capture

In a certain nucleus, the nucleus captures an electron from the K-shell (as it is near to the nucleus). The vacancy created is filled up with the electron from the higher shells thereby emitting X-rays. As a result of K-electron capture a proton in the nucleus is converted into a neutron (P+ e- n).


Advertisement
637.

72X180 2α β γ zXA , Z and A are :

  • 69 , 172

  • 172 , 69

  • 180 , 70

  • 182 , 68


638.

Assertion : The quantized energy of an electron is largely determined by its principal quantum number.

Reason : The principal quantum number n is a measure of the most probable distance of finding the electron around the nucleus.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


Advertisement
639.

Assertion : C- O bond in metal carbonyl is long.

Reason : There is delocalisation of electrons from filled d orbitals into the empty orbitals on the CO ligands.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false

  • If both assertion and reason are false.


640.

Isotopic pair is :

  • 20X4021X40

  • 20X40 , 20X41

  • 40X2041X20

  • None


Advertisement