LMS

Sample of radioactive element with initial mass of 24 gm decayed to 3 gm in 36 minutes.  How much of original sample remained after the first 12 minutes? 

C ¹⁴decays with a half-life of about 5800 years. In a sample of bone, the ratio of C ¹⁴to C ¹⁴is found to be 1/4th of what it is in free air. This bone may belong to a period about X centuries ago, where X is nearest to: 

Which is not radioactive? 

Protons and neutrons are composed of smaller particles called 

A nucleus emits an α- particle, followed by two β- particles. The final nucleus will be:

C14 has half-life 5700 years. At the end of 11400 years, the actual amount left is

A radioactive decay rate of 3.7 x 10 ¹⁰disintegrations per second defines the unit of measurement known as the 

Find the probability that the nucleus of 87Ra221 undergoes decay after three half-lives, if it’s a radioactive substance which has a half-life of 6 days. 

Absorbed dose D is defined as energy absorbed from ionization radiation per unit ___

If 238U decay two gamma particles the new atomic number will be 

Isotopes of an element have a different number of 

The fusion reaction is almost ____ times stronger than fission reaction

Two spherical nuclei have mass number 216 and 64 with radius R1 and R2 respectively.  The ratio of R2/R1 is 

Radiotherapy used in treatment of cancer usually use gamma-rays from

1 Curie is equal to 

_________ are such nuclei of an element that have the same mass number A, but have different charge number Z 

The radioactive isotope of Carbon is 

The Na atom cannot produce x-rays because 

Isotopes means addition of additional_____ in same proton number

One isotope of Uranium is U-238. Any other isotope of Uranium must have

What will be the means life of a source whose half-life is 1 hour? 

The radioactive element when decay to first half-life the new element is called:

Which reaction is endothermic: 

How many quarks in electron: 

Radon-222 has 136 neutrons, how many neutrons are there in Radon-220:

In fusion reaction of sun which element isotopes are used 

If a photon is absorbed by a electron the energy of electron 

What is the atomic number and mass number of Helium? 

What will be the decay constant of a material whose half-life is 1600 years in (year)^-1?

According to Bohr’s principle, what is the relation between the principal quantum number and the radius of the orbit? 

The charge and mass of photon is 

The deuterium atom has _____ quarks 

Iodine-131 is used to trace which cancer 

The source of gamma radiation is 

The isotope of 235U92 has _____ number of neutrons 

Radioactive material decays by simultaneous emission of two particles with respective half-lives 1620 and 810 years. The time, in years, after which one-fourth of the material remains? 

Numbers of neutrons present in a nucleus is given by 

Which element is used to absorb gamma radiations? 

What will happen in a time of 7 hours, if a radioactive substance has an average life of 7 hours? 

The unstable atom means 

A particle radioisotope has a half-life of 5 days. In 15 days, the probability of decay in percentage will be 

Which of the following is the same for isotopes? 

Which one of the following statements is correct 

How many down quarks in Neutron?

Which isotope has highest momentum when moving with same velocity

What will be the decay constant of substance whose half-life is 1 hour? Give your answer in (sec-1). 

Which set of elements have three isotopes 

Half-life of a radiation active element is that period in which half of the atoms:

The fission reaction is slow reaction: 

What is the unit of decay constant? 

Half-life of radioactive element means 

The artifacts and fossils are used to estimate ages by measured ______ content

The half-life of a radioactive substance is 40 years. How long will it take to reduce to one fourth of its original amount and what is the value of decay constant?

Whenever new nuclei are formed energy is 

SI unit of equivalent dose is 

If the nuclear radius of Al-27 is 3.6 fm, the approximate nuclear radius of Cu-64 in fermi is

Centrifuge is used to purify 

The radiations all around us are called_____ radiations 

1 barn is a unit of area having the magnitude of: