Neco Model Questions Vol1 2020 Physics Question 17

Practice objective / multiple choice question 17 from the 2020 Neco Model Questions Vol1 Physics examination.

Neco Model Questions Vol1 2020 Physics Objective / Multiple Choice Hard Difficulty
Question 17 NECO_MODEL_QUESTIONS_VOL1 • 2020 • PHYSICS • objective

A radioactive sample contains two isotopes, A and B, that both decay by beta emission. Isotope A has a half‑life of 5 min and an initial activity of 800 Bq. Isotope B has a half‑life of 20 min and an initial activity of 200 Bq. After a certain time the total activity of the sample is measured to be 500 Bq. Calculate the elapsed time (in minutes) to the nearest tenth.

Answer Options

A. 5.8 minutes (to the nearest tenth)
B. 4.9 minutes (to the nearest tenth)
Correct Answer C. 6.2 minutes (to the nearest tenth)
D. 7.4 minutes (to the nearest tenth)
Correct Answer
C
Correct Option:
6.2 minutes (to the nearest tenth)

About This Question

This is Neco Model Questions Vol1 2020 Physics Question 17. It is one of the objective questions from the 2020 Neco Model Questions Vol1 Physics examination.

Difficulty level: Hard .

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