TG EAMCET 2 May 2025 Shift 2 Paper

Step 1: Formula for Remaining Nuclei
We use the formula N=N0(‌

1

2

)n, where:
N= number of nuclei left
N0= starting number of nuclei
n= number of half-lives passed
Step 2: Setting Up the Ratio
The question asks for the ratio of nuclei left in A and B, so: ‌

NA

NB

=‌

( 1 2 )nA

(‌ 1 2 )nB

Step 3: Simplifying the Ratio
This simplifies to: ‌

NA

NB

=(‌

1

2

)nA−nB
Step 4: Finding Number of Half-lives for Each Substance
The number of half-lives n is found by dividing total time by half-life:
For A : nA=‌

9

1.5

=6
For B:nB=‌

9

4.5

=2
Step 5: Plugging In the Values
‌

NA

NB

=(‌

1

2

)6−2=(‌

1

2

)4
Step 6: Final Answer
(‌

1

2

)4=‌

1

16

So, the ratio of the remaining nuclei in A and B after 9 days is ‌

1

16

.