Passage II
When the nucleus of an atom of a radioactive isotope undergoes certain types of decay, the atom transforms into an atom of a different isotope. An isotope's half-life is the time it takes for half of any given number of its nuclei to decay. An isotope's decay constant, λ, depends on the isotope's rate of decay. Table 1 gives the value of λ (in 
) for 8 isotopes of different elements.
Figures 1 and 2 show, for each of 6 of the isotopes listed in Table 1, the change over time in the number of the nuclei remaining,
, in a sample initially containing 1,000 of the nuclei.
(Note: In Figure 1, the unit of time is years; in Figure 2, the unit of tine is days.)
8. According to Figure 2, for which isotope, S-35 or P-32, will the average rate of decay be greater over the first 200 days?
Your Answer is
Correct Answer is H
Explanation
The second and third lines under Table 1 say that Nt represents the number of remaining nuclei, so the faster Nt decreases, the greater the rate of decay;
Look In figure 2, it can be found that the line of P-32 is always lower than that of S-35, indicating that P-32 decays faster