Home
Class 12
PHYSICS
Half lives of two isotopes X and Y of a ...

Half lives of two isotopes X and Y of a material are known to be `2xx10^(9)` years and `4xx10^(9)` years respectively if a planet was formed with equal number of these isotopes, then the current age of planet, given that currently the material has `20%` of X and `80%` of Y by number, will be:

A

`8xx10^(9)` years

B

`6xx10^(9)` years

C

`4xx10^(9)` years

D

`2xx10^(9)` years

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • MODERN PHYSICS

    DC PANDEY|Exercise for JEE Advanced (only one option is Correct)|77 Videos

  • MODERN PHYSICS

    DC PANDEY|Exercise for JEE Advanced (More than One Options is Correct )|1 Videos

  • MAGNETISM AND MATTER

    DC PANDEY|Exercise Medical gallery|1 Videos

  • MODERN PHYSICS - 1

    DC PANDEY|Exercise Level 2 Subjective|23 Videos

Similar Questions

Explore conceptually related problems

Half lives of two isotopes X and Y of a material are known to be 2 xx 10^(9) years and 4 xx 10^(9) years respectively. If a planet was formed with equal number of these isotopes, then the current age of planet, given that currently the material has 20 % of X and 80 % of Y by number, will be

In the chemical analysis of a rock the mass ratio of two radioactive isotopes is found to be 100:1 . The mean lives of the two isotopes are 4xx10^9 years and 2xx10^9 years, respectively. If it is assumed that at the time of formation the atoms of both the isotopes were in equal propotional, calculate the age of the rock. Ratio of the atomic weights of the two isotopes is 1.02:1 .

Two numbers X and Y are respectively 20% and 28% less than a third number Z. By what percentage is the number Y less than the number X ?

The half of ""_(92)""^(238)U against alpha -decay is 4.5xx10""^(9) year. The time taken in year for the decay of 15/16 part of the isotope is

The present day abundances of the isotopes U^(238) and U^(235) are in the ratio of 128: 1. They have half lives of 4.5times10^(9) years and 7times10^(8) years respectively.If age of earth in (49X)/(76)times10^(7) years, then calculate X (Assume equal amount of each isotope existed at the time of formation of the earth)

A parent nucleus X is decaying into daughter nucleus Y which in turn decays to Z. The half lives of X and Y are 40000 years and 20 years respectively. In a certain sample, it is found that the number of Y nuclei hardly changes with time. If the number of X nuclei in the sample is 4 xx 10^(20) , the number of Y nuclei present in its is–

A sample of Uranium is a mixture of two isotopes ._(92)^(234)U and ._(92)^(238)U present in the ratio 10% and 90% by weight. The half lives of these isotopes are 2.5 xx10^(5) years and 4.5 xx10^(5) years respectively. Calculate the contribution to activity in percentage of each isotope in this sample.

DC PANDEY-MODERN PHYSICS-Integer Type Questions
  1. Half lives of two isotopes X and Y of a material are known to be 2xx10...

    Text Solution

    |

  2. The ratio between acceleration of the electron in singley ionized heli...

    Text Solution

    |

  3. If the radius of firs Bohr's orbit is x, then de-Broglie wavelenght of...

    Text Solution

    |

  4. A H-atom moving with speed v makes a head on collisioon with a H-atom ...

    Text Solution

    |

  5. The magnetic fieold at the centre of a hydrogen atom due to the motion...

    Text Solution

    |

  6. when the voltage applied to an X-ray tube increases from V(1) = 10 kV ...

    Text Solution

    |

  7. Light of wavelength 330nm falling on a piece of metal ejects electrons...

    Text Solution

    |

  8. Light of wavelength 0.6mum from a sodium lamp falls on a photocell and...

    Text Solution

    |

  9. An alpha-particle accelerated through V volt is fired towards a nucleu...

    Text Solution

    |

  10. The kinetic energies of the photoelectrons ejected from a metal surfac...

    Text Solution

    |

  11. In a hydrogen atom following the Bohr's psotulates the product of line...

    Text Solution

    |

  12. A target element A is bombarded with electrons and the wavelengths of ...

    Text Solution

    |

  13. A moving hydrogen atom makes a head on collision with a stationary hy...

    Text Solution

    |

  14. A radioactive sample contains two different types of radioactive nucle...

    Text Solution

    |

  15. A overset(lambda)rarr B overset(2 lambda)rarr C T=0 ,N(0) , 0 , T...

    Text Solution

    |

  16. In a photeclectric experiment , when electromegnetic wave given by E=E...

    Text Solution

    |

  17. Nuclei X and Y convert into a stable nucleus Z. At t=0 , the number o...

    Text Solution

    |

  18. Single electron is orbiting in n^(th)orbit of hydrogen atom. The magne...

    Text Solution

    |