Question Detail

PHY 104 PHY 104 Past Questions Objective Question
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Question

The average counting rate recorded by a detector fixed in front of an alpha particle emitter is 256 per second. What is the average counting rate 20 days later, if the half-life of the emitter is 5 days?
Options
A 32 per second
B 16 per second
Correct Answer
C 128 per second
D 64 per second
Correct Answer

Option B is the correct answer.

Detailed Explanation

20 days is 4 half-lives (20/5 = 4). Count rate = 256 × (1/2)^4 = 256/16 = 16 per second.

Hint

Count rate halves every half-life.

Question Info

Course: PHY 104
Topic: PHY 104 Past Questions
Type: Objective
Difficulty: Not specified
Question 914 of 947
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