Recent questions and answers in Atoms

The disintegration rate of a radioactive sample at a certain instant is 4750 dpm . Five minute later rate becomes 2700 disintegration per minute . Then the decay constant is

answered Feb 10, 2020 by ayomidevictoria002

2 answers

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

answered Mar 11, 2014 by yamini.v

1 answer

The half life of $\;^{215}At\;$ is $\;200 \mu s\;$ . The time taken for radioactivity of a sample of $\;^{215}At\;$ to decay to $\;{\large\frac{1}{4}}^{th}\;$ of its initial value is

answered Mar 11, 2014 by yamini.v

1 answer

The fast neutrons can easily be slowed down by :

answered Mar 6, 2014 by yamini.v

1 answer

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

answered Mar 6, 2014 by yamini.v

1 answer

A Beta decay is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted from an atomic nucleus. During a negative beta decay $\beta^{-}$, which of the following happens?

answered Mar 6, 2014 by yamini.v

1 answer

The binding energy per nucleon of deuteron $\;(_{1}^{2}H)\;$ and helium nucleus $\;(_{2}^{4}He)\;$ is 1.1 MeV and 7 MeV respectively . If two deuteron nuclei react to form a single helium nucleus, the energy released is

answered Mar 6, 2014 by yamini.v

1 answer

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 .

answered Mar 6, 2014 by yamini.v

1 answer

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

answered Mar 6, 2014 by yamini.v

1 answer

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?

answered Mar 6, 2014 by yamini.v

1 answer

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

answered Mar 6, 2014 by yamini.v

1 answer

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 :

answered Mar 6, 2014 by yamini.v

1 answer

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

answered 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

answered 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

answered 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

answered Feb 28, 2014 by yamini.v

1 answer

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

answered Feb 28, 2014 by yamini.v

1 answer

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

answered Feb 28, 2014 by yamini.v

1 answer

Which of the following is correct statement ?

answered Feb 28, 2014 by yamini.v

1 answer

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

answered Feb 28, 2014 by yamini.v

1 answer

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

answered Feb 28, 2014 by yamini.v

1 answer

A nucleus with mass number 200 initially at rest emits and $\;\alpha-\;$ particle . If Q value of reaction is 4.2MeV .Then kinetic energy of $\;\alpha-\;$ particle will be

answered Feb 28, 2014 by yamini.v

1 answer