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• CBSE×
• Class 12 Science×
• Physics×
• Nuclei×

CBSE - XII Science - Physics - Nuclei Asked by alanpeter9611 23rd February 2019, 7:47 PM

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CBSE - XII Science - Physics - Nuclei Asked by alanpeter9611 22nd February 2019, 11:24 PM

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Half-life period of a radioactive sample is 2 days. If the number of nuclei initially present is , find the number of nuclei present after 8 days?

Asked by sd2021667 4th December 2018, 4:46 PM

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Differentiate between alpha,beta and gamma decay.

Asked by pksunilnair 4th December 2017, 9:22 AM

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from boards point of view is it important to learn speed of emmitted alpha particle from the topic alpha decay?

Asked by vasturushi 4th November 2017, 12:23 PM

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A radioactive material of half-life T was produced in a nuclear reactor at different instants, the quantity produced second time was twice of that produced first time. If now their present activities are respectively then their age difference equals: (A) (B) (C) (D) Asked by yugibo 13th April 2016, 9:48 PM

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There are two radionuclei A and B. A is an alpha emitter and B is a beta emitter. Their distintegration constants are in the ratio of 1 : 2. What should be the ratio of number of atoms of two at time t = 0 so that probabilities of getting particles are same at time t = 0. (A) 2 : 1 (B) 1 : 2 (C) e (D) Asked by yugibo 13th April 2016, 9:35 PM

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The following table shows some measurements of the decay rate of a radionuclide sample .Find the disintegration constant .                        Time                                            lnR                         36                                              5.08                         100                                            3.29                          164                                            1.52                                                                             218                                            1.00

Asked by Rajeev 16th February 2016, 9:28 PM

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What is the half life period of carbon 14?

Asked by Balbir 30th September 2015, 9:15 PM

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Write symbolically the nuclear β+ decay process of. Is the decayed product X an isotope or isobar of ()? Given the mass values m () = 11.011434 u and m (X) = 11.009305 u. Estimate the Q-value in this process.

Asked by Topperlearning User 10th July 2015, 8:41 AM

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can a radioactive nucleus emit an alpha particle and a beta particle simultaneously?

Asked by haider.samina 7th March 2015, 10:40 AM

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A given number of atoms No of radio active element with half life T is uniformly distributed in a blood stream of a : 1)normal person, A having total volumn of blood,V 2)Person B in need of blood tranfusion having volumn,V' of blood in the body. The number of radioactive atoms per unit volumn in the blood streams of 2 persons after a time nT are found to be N1,N2. Prove mathematically that the additional volume of blood need to be tranfused in the body of B is [(N2-N1)/N2}V.

Asked by Preethu S 23rd February 2015, 10:24 AM

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why would a nucleus want to disintegrate and form a nuclei

Asked by Sourav Jha 6th February 2015, 8:07 AM

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At  a given instant there are 25% undecayed radioactive nuclei in a sample. After 10 sec, the number of undecayed nuclei is reduced to 12.5%. calculate a) mean life of the nuclei b)the time in which the number of undecayed nuclei will further reduce to 6.25% of the reduced number.

Asked by Duwanie 25th November 2014, 12:20 AM

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What are -particles? In the reaction give the atoms number and mass number of Y.

Asked by Topperlearning User 9th July 2014, 6:53 PM

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A radioactive sample contains 2.2 mg of pure which has half life period of 1224 seconds. Calculate (i) the number of atoms present initially. (ii) the activity when 5μg of the sample will be left.

Asked by Topperlearning User 9th July 2014, 6:46 PM

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State radioactive decay law and hence derive the relation N = No e-λt where symbols have their usual meanings

Asked by Topperlearning User 9th July 2014, 5:10 PM

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A radioactive uncleus undergoes a series of decay according to the scheme If the mass number and atoms number of A are 180 and 72 respectively, what are there number for A4?

Asked by Topperlearning User 9th July 2014, 4:44 PM

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Define decay constant of a radioactive sample. Which of the following radiation α-rays, β-rays and y-rays, (i) Are similar to x - rays? (ii) Are easily absorbed by matter?

Asked by Topperlearning User 9th July 2014, 4:26 PM

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Complete the following nuclear reactions (a) 4Be9 + 1H1 →3Li6 + ................ (b) 5B10 + → + ..............

Asked by Topperlearning User 9th July 2014, 4:15 PM

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How many α and β-partiles are emitted 90Th232 changes to 82Pb208?

Asked by Topperlearning User 9th July 2014, 4:06 PM

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Calculate the amount of energy released during the decay of Given : 1.atomic mass of =238.05079u 2. atomic mass of = 234.04363 3.atomic mass of = 4.00260  lu = 931.5 MeV/c2. Is this decay spontaneous? Give reason.

Asked by Topperlearning User 9th July 2014, 3:56 PM

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State the law of radioactive decay. Plot a graph showing the number (N) of undecayed nuclei as a function of time (t) for a given radioactive sample having half life T1/2. Depict in the plot the number of undecayed nuclei at (i) t = 3 T1/2 and (ii) t = 5 T1/2.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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(i) Define 'activity' of a radioactive material and write its S.I. unit. (ii) Plot a graph showing variation of activity of a given radioactive sample with time. (iii) The sequence of stepwise decay of a radioactive nucleus is If the atomic number and mass number of D2 are 71 and 176 respectively, what are their corresponding values for D?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The radioactive isotope D decays according to the sequence If the mass number and atomic number of are 176 and 71 respectively, what is (i) the mass number (ii) atomic number of D?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Explain, with the help of a nuclear reaction in each of the following cases, how the neutron to proton ratio changes during (i) alpha- decay (ii) beta-decay?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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State the law of radioactive decay. Plot a graph showing the number (N) of undecayed nuclei as a function of time (t) for a given radioactive sample having half life

Asked by Topperlearning User 4th June 2014, 1:23 PM

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(i) Define 'activity' of a radioactive material and write its S.I. unit. (ii) Plot a graph showing variation of activity of a given radioactive sample with time. (iii) The sequence of stepwise decay of a radioactive nucleus is If the atomic number and mass number of D2 are 71 and 176 respectively, what aretheir corresponding values for D?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The ground state energy of hydrogen atom is -13.6eV (i) What is the kinetic energy of an electron in the second excited state ? (ii) If the electron jumps to the ground state from the second excited state, calculate the wavelength of the spectral line emitted.   OR

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Define ionisation energy. What is its value for hydrogen atom?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Give the mass number and atomic number of elements on the right hand side of the decay process.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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Define half life  of a radioactive element. Write its S.I. unit. derive expression for half life?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A radioactive nuclide decays to form a stable nuclide its half life is 3 minutes. What fractions of its 1g will remain radioactive after 9 minutes?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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If the activity of a radioactive substance drops to 1/8 th of its initial value in 30 years, find its half life period?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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A neutron is absorbed by a 3Li nucleus with subsequent emission of alpha particle. Write the corresponding nuclear reaction?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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What fraction of tritium will remain after 25 years? Given half life of tritium as 12.5 years.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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The half life period of a radioactive substance is 30 days. What is the time for Â¾ th of its original mass to disintegrate?

Asked by Topperlearning User 4th June 2014, 1:23 PM