Recent questions tagged atoms-and-nuclei

A proton is bombarded on a stationary lithium nucleus. As a result of collision two $\;\alpha\;$ particles are produced . If direction of motion of $\;\alpha \;$ particle with initial direction of motion makes an angle $\;cos^{-1}(\large\frac{1}{4})\;$ find kinetic energy of striking proton . Given binding energies per nucleon of $\;Li^{7}\;$ & $\;He^{4}\;$ are $5.60 MeV$ and $7.06 MeV$ respectively

asked Mar 11, 2014 by yamini.v

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The fast neutrons can easily be slowed down by :

asked Mar 6, 2014 by yamini.v

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Consider $\;\alpha\;, \beta \;, \gamma\;$ rays each having an energy 1 MeV . Arrange them in increasing order of penetrating powers of radiation.

asked Mar 6, 2014 by yamini.v

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If a nucleus disintegrates i two two nuclear parts which have their velocities in ratio 2 : 1 . The ratio of their nuclear sizes will be .

asked Mar 6, 2014 by yamini.v

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In a sample of radioactive substance what fraction of initial no . of nuclei will remain undecayed after time $\;t=\large\frac{T}{2}\;$ , where T = half - life of substance

asked Mar 6, 2014 by yamini.v

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At time zero, there are 10.0 grams of W-187. If the half-life is 23.9 hours, how much will be present at the end of seven days?

asked Mar 6, 2014 by yamini.v

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In a radioactive process nucleus X finally transforms into a stable nucleus Y . Then X & Y can be :

asked Mar 6, 2014 by yamini.v

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A radioactive nucleus is being produced at a constant rate x per second . If decay constant is K . If $\;N_{0}\;$ are no . of nuclei at time t=0 , then maximum no . of nuclei possible are :

asked Mar 6, 2014 by yamini.v

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There are two radioactive substances X & Y . If Decay constant of Y is 2 times of X . Initially both have equal number of nuclei . Then after n half lives of X rate of disintegration of both are equal . The value of n is

asked Mar 6, 2014 by yamini.v

1 answer

If activity of a radioactive substance's $\;A_{1}\;$ at time $\;t_{1}\;$ & $\;A_{2}\;$ at time $\;t_{2}\;$ $\;(> t_{1})\;$ . Its decay constant is $\;\lambda\;$ . Then no . of atoms decayed between time $\;t_{1}\;$ & $\;t_{2}\;$ are

asked Mar 6, 2014 by yamini.v

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If activity of a radioactive substance's $\;A_{1}\;$ at time $\;t_{1}\;$ & $\;A_{2}\;$ at time $\;t_{2}\;$ $\;(> t_{1})\;$ . Its decay constant is $\;\lambda\;$ . Then

asked Feb 28, 2014 by yamini.v

1 answer

If ratio of molecular masses of two radioactive substances is $\;\large\frac{1}{2}\;$ and ratio of decay constant is $\;\large\frac{5}{3}\;$ . Then ratio of their initial activity per mole will be

asked Feb 28, 2014 by yamini.v

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x atoms of a radioactive element emit y beta particles per second . Then the decay constant of element is (in $\;s^{-1}$) .

asked Feb 28, 2014 by yamini.v

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The equation : \[\] $\;4 _{1}^{1}H \to _{2}^{4}He^{2+}+2e^{-}+32 MeV\;$ represents

asked Feb 28, 2014 by yamini.v

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Which of the following is correct statement ?

asked Feb 28, 2014 by yamini.v

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$\;^{22}Ne\;$ Nucleus after absorbing energy , decays into two $\;\alpha-\;$ particles and an unknown nucleus . The unknown nucleus is

asked Feb 28, 2014 by yamini.v

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The half -life period of a radioactive element A is same as mean life of another radioactive element B . Initially both of them have same number of atoms

asked Feb 28, 2014 by yamini.v

1 answer