May/June 2026 Paper 23

2026 · 40 questions · 40 parts · 40 marks

0/40 marks
0Correct0Partial0Wrong40Unattempted
Filters0 active

Questions

Select a part to jump to its question

Finish set
Q1
1
–/1 mk
Q2
2
–/1 mk
Q3
3
–/1 mk
Q4
4
–/1 mk
Q5
5
–/1 mk
Q6
6
–/1 mk
Q7
7
–/1 mk
Q8
8
–/1 mk
Q9
9
–/1 mk
Q10
10
–/1 mk
Q11
11
–/1 mk
Q12
12
–/1 mk
Q13
13
–/1 mk
Q14
14
–/1 mk
Q15
15
–/1 mk
Q16
16
–/1 mk
Q17
17
–/1 mk
Q18
18
–/1 mk
Q19
19
–/1 mk
Q20
20
–/1 mk
Q21
21
–/1 mk
Q22
22
–/1 mk
Q23
23
–/1 mk
Q24
24
–/1 mk
Q25
25
–/1 mk
Q26
26
–/1 mk
Q27
27
–/1 mk
Q28
28
–/1 mk
Q29
29
–/1 mk
Q30
30
–/1 mk
Q31
31
–/1 mk
Q32
32
–/1 mk
Q33
33
–/1 mk
Q34
34
–/1 mk
Q35
35
–/1 mk
Q36
36
–/1 mk
Q37
37
–/1 mk
Q38
38
–/1 mk
Q39
39
–/1 mk
Q40
40
–/1 mk
37Half Life Exponential DecayHard1 mark
Oxygen-15 is used in hospitals. The count rate from a detector placed close to a sample of oxygen-15 was recorded over a period of 15 min. The background count rate is 20 counts / min. The graph shows the total count rate from the detector.
a count-rate graph from 0 to 15 minutes, a smooth decay curve starting at 180 counts/min and falling to level off around 20 counts/min (the background rate) by about 12 minutes, passing through 100 at 2 min and 40 at 6 min
What is the half-life of this sample of oxygen-15?