The mass, $m$ grams, of the decomposition of a radio-active substance is given by the formula \(m

Question

The mass, $m$ grams, of the decomposition of a radio-active substance is given by the formula $m = ae^{-bt}$, where $a$ and $b$ are constants, and $t$ is the number of weeks after the initial measurement of the mass. Experimental values of $t$ and $m$ are given in the table below. $t$$1$$2$$3$$4$$5$ $m$$1.51$$0.454$$0.137$$0.0183$$0.0124$ What does the constant $a$ refer to?[1] By drawing a suitable straight line graph using the data provided, estimate the value of $a$ and of $b$.[7] It is discovered that one of the readings of the mass, $m$, is incorrect. Using your graph, estimate the correct value for this incorrect reading.[2]

Accepted Answer

(ii)a =4.95, b =1.19 (iii)corrected value of m = 0.0429

2025 AHS PRELIMS P1 Q14

2025 AHS PRELIMS P1 Q14