Home
Class 12
PHYSICS
After how many days will 1/20 th of the ...

After how many days will `1/20 th` of the radio active element remain behind, if half life of the element is 6.931days

A

`23.03days`

B

`25.12 days`

C

`29.96 days`

D

`27.12 days`

Text Solution

Verified by Experts

The correct Answer is:
C
As `lambda=0.6931/T =0.6931/6.931=0.1` per day
Now `N/(N_(0))=e^(-lambdat)`
or `1/20=e^(-0.1t)`
`e^(+0.1t)=20 or 0.1t=2.303log _(10)20`
`0.1t=2.303xx1.3010`
`t=29.96` days
Promotional Banner

Topper's Solved these Questions

  • ATOMS AND NUCLEI

    PRADEEP|Exercise Fill in the blank 2|1 Videos

  • ATOMS AND NUCLEI

    PRADEEP|Exercise Multiple choice questions 1|1 Videos

  • ATOMS AND NUCLEI

    PRADEEP|Exercise curiocity quetions 3|1 Videos

  • COMMUNICATION SYSTEMS

    PRADEEP|Exercise MODEL TEST PAPER-2|9 Videos

Similar Questions

Explore conceptually related problems

After how many days will 1/20th of the radioactive element remain, if the half life of the element is 6.931 days?

When 64 gms of a radioactive element are carried from Jaipure to Jodhpur in 2 hours. Then 1 gm of active element remains . The half life of the element is -

How long will it take for 75% of the atoms of a certain radioactive element, originally present to disintegrate ? The half-life of the element is 10 days.

Half life of a radioactive element is 10 days. What percentage of the element will remain undecayed after 100 days?

What is the relation between decay constant and half life of a radio active element?

A saample of radioactive elements contains 4xx10^(16) active nuclei. If half-life of element is 10 days, then the number of decayed nuclei after 30 days is

After an interval of one day , 1//16th initial amount of a radioactive material remains in a sample. Then, its half-life is .

The half-life period of a radioactive element is 140 day. After 560 days, 1 g of the element will reduce to

If 1/16 th of a usbstance is left after 40 days then the half life is

PRADEEP-ATOMS AND NUCLEI-Exercise
  1. A nuclear power supplying electrical power to a villages uses a radioa...

    Text Solution

    |

  2. Uranium ores on the earth at the present time typically have a composi...

    Text Solution

    |

  3. After how many days will 1/20 th of the radio active element remain be...

    Text Solution

    |

  4. Radioactive material 'A' has decay constant '8 lamda' and material 'B'...

    Text Solution

    |

  5. The number of beta particles emitter by radioactive sustance is twice ...

    Text Solution

    |

  6. In a sample of radioactive material, what percentage of the initial nu...

    Text Solution

    |

  7. C^(14) has life 5700 yrs. At the end of 11400 yers, the actual amount...

    Text Solution

    |

  8. Two radioactive materials have decay constant 5lambda&lambda. If initi...

    Text Solution

    |

  9. A freshly prepared radioactive sample of half life 1 hour emits radiat...

    Text Solution

    |

  10. A radio isotope X with a half-life 1.4 xx 10^9 years decays of Y which...

    Text Solution

    |

  11. In a radioactive material the activity at time t1 is R1 and at a later...

    Text Solution

    |

  12. The intensity of gamma radiation from a given source is I On passing...

    Text Solution

    |

  13. To determine the half life of a radioactive element , a student plote ...

    Text Solution

    |

  14. A radiaoactive nucleus (initial mass number A and atomic number Z emit...

    Text Solution

    |

  15. The activity of a radioactive sample is measures as N0 counts per minu...

    Text Solution

    |

  16. The speed of daugther nuclei is

    Text Solution

    |

  17. The decay constant of radio isotope is lambda. If A(1) and A(2) are it...

    Text Solution

    |

  18. A radioactive isotope has a life of T years. How long will it take the...

    Text Solution

    |

  19. Two samples X and Y contain equal amounts of radioactive substances. I...

    Text Solution

    |

  20. The activity of a freshly prepared radioactive sample is 10^(10) disin...

    Text Solution

    |