The half-lives of two radioactive nuclides A and B are 1 and 2 min respectively. Equal weights of A and B are taken separately and allowed to disintegrate for 4 min. What will be the ratio of weights of A and B disintegrated
A. 1:1
B. 5:4
C. 1:2
D. 1:3
Which of the following is correct ?
A. 1H1 and 2He3 are isotopes
B. 6C14 and 7N14 are isotopes
C. 19K39 and 20Ca40 are isotones
D. 9F19 and 11Na24 are isodiaphers
Atoms of different elements having identical mass are known as :
A. isotopes
B. isobars
C. isotones
D. isomers
A radioactive substance 88X228 (IIA) emits 3α and 3β particles to form "Y". To which group of long form of the periodic table does "Y" belong
A. IVA
B. VA
C. VIA
D. VIIA
which of the following is not correcr?
A. 20Ca40and 18Ar40are isotones
B. Nuclei of atoms participate in nuclear reactions
C. Uranium (U238) series is known as (4n+2) series
D. 1 amu of mass defect is approximately equal to 931.5 MeV
The half-life period of a radioactive element is 120 days. After 480 days 4.0 gm of the element will be reduced to (.....) gms.
A. 2.0
B. 1.0
C. 0.5
D. 0.25