A count rate meter shows a count of `240` per minute from a given radioactive source. One hour later the meter shows a count rate of `30` per minute. The half-life of the source is.

A count rate meter shows a count of 240 per minute from a given radioactive source. One hour later the meter shows a count the rate of 30 per minute. The half-life of the source is

A counter gives a count of 320 counts/minute for a radioactive source . After 75 minutes, the counter shows a count rate of 40 counts/minute . What is the half life period of the source ?

A counter rate - meter is used to measure the activity of a given sample. At one instant, the meter show 4750 counts per minute. Five minutes later it shows 2700 counts per minute. The half-life of the sample is nearly ______ minute [log_(10)^(1.760)=0.2455]

The count rate meter is used to measure that activity of a given amount of a radio active element. At one instant, the meter shows 475 counts/minute. Exactly 5 minutes later, is shown 270 counts/minute then The decay constant is

The count rate meter is used to measure that activity of a given amount of a radio active element. At one instant, the meter shows 475 counts/minute. Exactly 5 minutes later, is shown 270 counts/minute then Half life of the sample is (in minute)

The count rate meter is used to measure that activity of a given amount of a radio active element. At one instant, the meter shows 475 counts/minute. Exactly 5 minutes later, is shown 270 counts/minute then Find Half life of the sample is (in minute)

The count rate meter is used to measure that activity of a given amount of a radio active element. At one instant, the meter shows 475 counts/minute. Exactly 5 minutes later, is shown 270 counts/minute then Half life of the sample is (in minute)

The count rate meter is used to measure that activity of a given amount of a radio active element. At one instant, the meter shows 475 counts/minute. Exactly 5 minutes later, is shown 270 counts/minute then Mean life of the sample is ( in minutes)

A sample contanining a radioactive isotope prduces 2000 counts per minutes in a Giege counter. Afte 120hours, the sample produces 250 counts per minutes. What is the half-life of the isotope?