For a complete decay ______time is required.

Alpha particles are more damaging than x-rays by_____times

Neutrons mainly cause damage to:

A radioactive element of half life 5days decays 7/8th of its sample in how many days?

A radioactive element of half life 24,000 years is stored up to 72,000 years.What fraction of it remains?

If the radioactive substance reduces to 1/16 of its original mass in 40 days then its half-life is

1 micro Curie of radioactivity is equal to

The half-life of radium is about 1600 years. If a rock initially contains 1 g of radium, the amount left after 6400 years will be about

Radioactive 90Sr has a half-life of 30 years. What percent of a sample of 90Sr will remain after 60 years?

A count rate 240 per minute reduce to 30 counts per min in 1 hour. The half-life of source is

210Bi (an isotope of bismuth) has a half-life of 5.0 days. The time for three-quarters of a sample of 210Bi to decay is:

g- radiation are emitted due to

Absorbed dose is defined as

Emission of radiation from radioactive element is:

The half-life of is 5 days, if we start with 50, 000 atoms of this isotopes, the number of atoms left over after 10 days is

The number of neutron in ⁷₃Li are:

A beta particle is fast moving electron. During beta -decay how the Z and A of nucleus changes?

The value of a in the following reaction is

⁹₄Be+ ⁴₂He= ^a₆C +¹₆n

Ten grams of kept in an open container beta-decays with a half-life of 270 days. The weight of the material inside the container after 540 days will be very nearly

The percentage of the original of a radioactive material left after five half-lives is approximately

If 20 g of a radioactive substance reduces to 10 g in 4 minutes, then in what time will 80 g of the same substance reduce to 10 g?

Different radioactive materials have

The isotopes I-131 is used in the treatment of:

cobalt-60 is used for treatment of

The radioactivity of a nucleus becomes 1/64 of its initial value in 60 seconds. The half-life of nuclide is

Half-life of a radioactive element is:

There is no change in A and Z of any radioactive element by the emission of

⁹⁰₃₈Sr decays to ⁹⁰₃₉Y by

A radioactive substance is at t=0, the number of atoms is 8×104. Its half-life period is 3 years. The number of atoms 1×104will remain after interval

The decay constant of radium is 4.28×10-4 per year. Its half-life will be

A sample contains 16 gm of a radioactive material, the half-life of which is two days. After 32 days, the amount of radioactive material left in the sample is

Half-life of a radioactive substance is T. The time taken for all the nuclei to disintegrate will be

For skin cancer which of following can be used:

The half-life of a radioactive element which has only 1/32 of its original mass left after a lapse of 60 days is

Radioactivity is

The atomic number of an element is:

In which radioactive disintegration, neutron dissociates into proton and electron

A quark cannot have charge

The activity of radioactive sample:

During nuclear changes which of the following laws remain applicable

What percentage of radioactive substance is left after three half-lives?

The rate of decay of radioactive element at a given instant of time is 103 disintegration/second. If the half-life of this element is 1 second, then the rate of decay after 2 second will be

Among the three types of radioactive radiation, which have strongest penetration power?

The initial activity of a sample of a radioactive isotope containing N0 nuclei is A0. What is the number of unchanged nuclei when the activity has declined to A•/2

One eight of the initial mass of certain radioactive isotope remains un-decayed after one hour. The half-life of the isotope in minutes is

Curie is a unit of

Three quarks make up a

Activity of a sample is initially 320 counts per second. At the end of 90 minutes it gives 40 counts per second. What is the half-life of the element in sample?

Which of given is not correct