TG EAMCET 4 May 2025 Shift 1 Paper

The mass number of a nucleus is shown by A.
The radius of a nucleus depends on the mass number as R=R0A1∕3, where R0 is a constant.
To compare the radii of two nuclei, use the formula:
‌

R1

R2

=(‌

A1

A2

)1∕3
Here, ‌

A1

A2

=‌

27

125

.
So,
‌

R1

R2

=(‌

27

125

)1∕3=‌

3

5

because 271∕3=3 and 1251∕3=5.
The surface area of a sphere is S=4πR2.
The ratio of their surface areas is:
‌

S1

S2

=‌

4πR12

4πR22

=(‌

R1

R2

)2=(‌

3

5

)2=‌

9

25

So, the ratio of their surface areas is S1:S2=9:25.