23.2 Radioactive decay

understand that fluctuations in count rate provide evidence for the random nature of radioactive decay.

Use —fluctuations in count rate provide evidence for the random nature of to connect the rule to the data and decision in the question.

This matters because —fluctuations in count rate provide evidence for the random nature of determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —fluctuations in count rate provide evidence for the random nature of to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Fluctuations in count rate provide evidence for the random nature of is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand that radioactive decay is both spontaneous and random.

Use —radioactive decay is both spontaneous and random to connect the rule to the data and decision in the question.

This matters because —radioactive decay is both spontaneous and random determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —radioactive decay is both spontaneous and random to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Radioactive decay is both spontaneous and random is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

define activity and decay constant, and recall and use A = λN.

Use —activity and decay constant, and recall and use a = λn to connect the rule to the data and decision in the question.

This matters because —activity and decay constant, and recall and use a = λn determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —activity and decay constant, and recall and use a = λn to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Activity and decay constant, and recall and use A = λN is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

define half-life.

Use —half-life to connect the rule to the data and decision in the question.

This matters because —half-life determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —half-life to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Half-life is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

use λ = 0.693 / t 1/2.

Use —λ = 0.693 / t 1/2 to connect the rule to the data and decision in the question.

This matters because —λ = 0.693 / t 1/2 determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —λ = 0.693 / t 1/2 to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Λ = 0.693 / t 1/2 is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

understand the exponential nature of radioactive decay, and sketch and use the relationship x = x 0e–λt, where x could represent activity, number of undecayed nuclei or received count rate.

Use —the exponential nature of radioactive decay, and sketch and use the to connect the rule to the data and decision in the question.

This matters because —the exponential nature of radioactive decay, and sketch and use the determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the exponential nature of radioactive decay, and sketch and use the to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The exponential nature of radioactive decay, and sketch and use the is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.