The radioactive decay of a substance is given by
R=1000e−ct,t≥0. R = 1000e^{-ct}, \quad t \geq 0. R=1000e−ct,t≥0.where R R\,R is the number of atoms at time t t\,t years and c c\,c is a positive constant.
Find the number of atoms when the substance started to decay.
It takes 5730 years for half of the substance to decay. Find the value of c c\,c to 3 significant figures.
Calculate the number of atoms that will be left when t=22,920t = 22,920t=22,920.
Sketch the graph of R R\,R against ttt.
Practise Edexcel A Level Old Maths Logs with exam-style questions for A Level Old Maths. 16 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.