Home
Class 12
CHEMISTRY
A Geiger melter countries is used to stu...

A Geiger melter countries is used to study , the radicuacting process in the abserence of radoactive substance A , it couts `2` disingration per second (dps) Al the start in due presence of A, it recoirds `23` dps and after `10` in 3 dps,
(i) What does it count after `20` min?
(ii) What is the half -life A?

A

`8 dps,10 min`

B

`5 dps,10 min`

C

`5 dps,20 min`

D

`5 dps,5 min`

Text Solution

Verified by Experts

The correct Answer is:
a
In the absence of `A,3 `dps is zero error hence
Initial count `= 23 - 3 = 20 dps`
After `10 min= 13 - 3 = 10 dps`
After `20 min= 5 dps("recorded" = 5 + 3 = 8 dps)`
`(50%` fall in `10 min T_(so) = 10 min)`
Promotional Banner

Topper's Solved these Questions

  • MOCK TEST

    A2Z|Exercise Single correct Answer type question|40 Videos

  • MOCK TEST

    A2Z|Exercise Assertion-Reasoning|5 Videos

  • GENERAL PRINCIPLES AND PROCESS OF ISOLATION OF METALS

    A2Z|Exercise Section D - Chapter End Test|30 Videos

  • ORGANIC COMPOUNDS CONTAINING HALOGENS

    A2Z|Exercise Section D - Chapter End Test|30 Videos

Similar Questions

Explore conceptually related problems

A Geigger Muller counter is used to study the radioactive process. In the absence of radioactive substances A , it counts 3 disintegration per second (dps). At the start in the presence of A , it records 23 dps, and after 10 m in 13 dps , i. What does it count after 20 m in ?

Ram was a daily wage worker in a factory. He was suffering from Cancer. On hearing this, most of his co-workers, started avoiding him under the impression that it was a contagious disease. When Prof. Srivastava came to know about this, case, he took him to a leading radiologist, who examined him and told that it was at the beginning stage. He advised that it could be easily cured and also certified that it was not a communicable disease. After this, Ram was given proper treatment by the doctor and got cured completely. (1) What moral values did Prof. Srivastava display ? (2) How is mean life of a radioactive element related to its half life? (3) A radioactive sample has activity of 10,000 disintegrations per second after 20 hours . After next 10 hours, its activity reduces to 5,000 dps. Find out its half - life and initial activity.

In a village, farmers started cultivating crops all around a lake which was always filled with water. They added lot of materials W to the soil in their fields to increase the yield of crops. Soon they found that the whole surface of water in the lake was covered with a green layer made up of tiny organisms X. After some time, the fish present in the lake started dying in large numbers they could not get sufficient Y due to a process Z which had occurred in lake water and drained out all the Y present in the water of lake. (a) What do you think materials W are ? (b) Name (i) X, and (ii) Y. (c ) What is the process Z known as ? (d) What happens during the process Z which uses up all the Y present in lake water ? (e) What does this example tell us about the use of materials like W ?

A chemist prepares 1.00 g of pure ._(6)C^(11) . This isotopes has half life of 21 min, decaying by the equation: a. What is the rate of disintegration per second (dps) at starts ? b. What is the activity and specific activity of ._(6)C^(11) at start? c. How much of this isotope (._(6)C^(11)) is left after 24 hr its preparation?

(a) A radioactive sample has 6.0 xx 10^(18) active nuclei at a certain instant. How many of these nuclei will still be the same active state after two half-lives? (b) Radioactive phosphours -32 has a half-life of 14 days. A source containing this isotope has an initial activity of 10muCi . (i) What is the activity of the source after 42 days? (ii) What time elapse before the activity of the source falls at 2.5muCi ? (c) 1g of a radioactive substance disintergrates at the rate of 3.7 xx 10^(10) dps . The atomis mass of the substance is 226 . Calculate its mean life.

In the study of titration of NaOH and Na_(2)CO_(3) . NaOH and NaHCO_(3) , Na_(2)CO_(3) and NaHCO_(3) , phenophthalein and methyl orange are used as indicators. (a). When phenolphthalein is used as an indicator for the above mixture: (i). It indicates complete neutralisation of NaOH or KOH (ii). It indicates half neutralisation of Na_(2)CO_(3) because NaHCO_(3) is formed at the end point. (b). When methyl orange is used as an indicator for the above mixture (i). It indicates complete neutralisation of NaOH or KOH (ii). It indicates half neutralisation of Na_(2)CO_(3) because NaCl is formed at the end point. Q. 1 L solution of Na_(2)CO_(3) and NaOH was made in H_(2)O . 100 " mL of " this solution required 20 " mL of " 0.4 M HCl in the presence of phenolphthalein however, another 100 mL sample of the same solution required 25 " mL of " the same acid in the presence of methyl orange as indicator. What is the molar ratio of Na_(2)CO_(3) and NaOH in the original mixture.

Two linear parallel conductors carrying currents in the same direction attract each other and two linear parallel conductors carrying currents in opposite direction repel each other. The force acting per unit length due to currents I_1 and I_2 in two linear parallel conductors held distance r apart in vacuum in SI unit is F=(mu_0)/(4pi)(2I_1I_2)/(r) Read the above passage and answer the following questions: (i) What is the basic reason for the force between two linear parallel conductors carrying currents? (ii) Two straight wires A and B of lengths 2cm and 20cm , carrying currents 2*0A and 5*0A respectively in opposite directions are lying parallel to each other 4*0cm apart. The wire A is held near the middle of wire B. What is the force on 20cm long wire B? (iii) What does this study imply in day to day life?

A2Z-MOCK TEST-Mock Test 2
  1. A Geiger melter countries is used to study , the radicuacting process ...

    Text Solution

    |

  2. What is the density of Na(2)O having antifluorite-type crystgal stryct...

    Text Solution

    |

  3. In the calcum fluaride structure, the coordination bumber of the catio...

    Text Solution

    |

  4. Assuming each salt to be 90% dissociated which of the following will h...

    Text Solution

    |

  5. When a solution is separated from a solvent by a semi-permeable membra...

    Text Solution

    |

  6. The values of wedge(m)^(oo) forNH(4)Cl,NaOH, and NaCl are, respectivel...

    Text Solution

    |

  7. 0.5F of electricity is passed through 500mL of copper sulphate solutio...

    Text Solution

    |

  8. Rate constant of a reaction with a virsus is 3.1 xx 10^(-4) s^(-1). Ti...

    Text Solution

    |

  9. 2N2O5 rarr 4 NO2 +O2 If -(D[N2O5])/(dt) =k1[N2O5] (d[NO2])/(dt) =k...

    Text Solution

    |

  10. Of which of the following colloidal systems, fog is an example?

    Text Solution

    |

  11. Soaking of water by a sponge is an example of

    Text Solution

    |

  12. A radioisotope has half life of 10 years. What percentage of the origi...

    Text Solution

    |

  13. When .(92)U^(238) decauys it emits an a-particle. The new nuclide in t...

    Text Solution

    |

  14. A will ……..by E1 reaction .

    Text Solution

    |

  15. Major product of this reaction is .

    Text Solution

    |

  16. CH3CH2CHO overset (NaOH, Delta) underset((aldol)) (rarr)A,A is.

    Text Solution

    |

  17. An optically active compound X has molecular formular C4H8 O3. It e...

    Text Solution

    |

  18. What is the end product of following reaction . overset ((i) H...

    Text Solution

    |

  19. . overset (HNO2) (rarr) A (Major product ), A is .

    Text Solution

    |

  20. Which A gives red colour in the reaction A overset ((i) HNO2)unders...

    Text Solution

    |

  21. Of the follwing , the most acidic is .

    Text Solution

    |