Mean life
t
[T]
s
Time at which number of
nuclei has been reduced to
e–1 of its initial value
Activity of a radio-
R
[ T–1]
Bq
Measure of the activity
active sample
of a radioactive source Rationalised 2023-24
Physics
320
POINTS TO PONDER
1 The density of nuclear matter is independent of the size of the nucleus The mass density of the atom does not follow this rule