If radius of first Bohr's orbit of hydrogen atom is 'x', then the

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

181.

The element Th90232 belongs to thorium series. Which of the following will act as the end product of the series?

  • 82Pb208

  • 82Bi209

  • 82Pb206

  • 82Pb207


Advertisement

182.

If radius of first Bohr's orbit of hydrogen atom is 'x', then the de-Broglie wavelength of electron in 3rd orbit is nearly

  • 2πx

  • 6πx

  • 9x

  • x/3


B.

6πx

As, rn = r0n2Zr3 = 32. x= 9xAlso, mv = nnh2π  mv=nh2πr3=3h2π9x=h6πxλ=hmv=h× 6πxh= 6πx


Advertisement
183.

Which of the following notations shows the product incorrectly?

  • B510 (α, n) N713

  • Cm96242 (α, 2n) Bk97243

  • N714 (n, p) C614

  • Si1428 (d, y) P1530


184.

Quantum numbers l = 2 and m= 0 represent the orbital

  • dxy

  • dx2-y2

  • dz2

  • dxz


Advertisement
185.

The wavelength of associated wave of a particle moving with a speed of one-tenth that of light is 7Å. The particle must be

  • electron

  • proton

  • nanoparticle

  • photon


186.

Which mathematical statement did not prove false?

  • E= hv

  • R=me48ε02h3c

  • R=n12n22v(n12-n22)c

  • mvr= nh2π


187.

Np93239 is a β- emitter, but the product is also radioactive and give 235U. Which particles(s) is/ are emitted by the product?

  • 4 neutrons

  • 4 protons

  • 4 protons and 2electrons

  • 2 neutrons and 2 protons


188.

For a f-orbital, the values of m are

  • -1, 0, +1

  • 0, +1, +2, +3

  • -2, -1, 0, +1, +2

  • -3, -2, -1, 0, +1, +2, +3


Advertisement
189.

A radio isotope will not emit

  • gamma and alpha rays simultaneously

  • gamma rays only

  • alpha and beta rays simultaneously

  • beta and gamma rays simultaneously


190.

A lone pair of electrons in an atom implies

  • a pair of valence electrons not involved in bonding

  • a pair of electrons involved in bonding

  • a pair of electrons

  • a pair of valence electrons


Advertisement