Np93239 is a β- emitter, but the product

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 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


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


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


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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


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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


D.

2 neutrons and 2 protons

On emission of a β  from the nucleus, the new element formed possesses the same atomic mass but nuclear charge or atomic number is increased by one unit over the parent element followmg reaction takes place.

     Np93239 -β Z94239

Number of protons in U-235 = 92

Product has an atomic number two units less than Z94239 and a mass number four units less than Z94239.

Hence, Z emits an alpha (α)  particle which contain 2 protons and 2 neutrons.

 Z94239 -(2p and 2n)-α U23592


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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


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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


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