TG EAMCET 3 May 2025 Shift 2 Paper

First Condition
When the current flows normally, the formula for the potential difference across the cell is: V=E− ir
We are given that V=20V and i=2A. Plug these values into the formula:
20=E−2r
Second Condition
When the current direction is reversed, the formula for potential difference becomes: V=E+ir.
Here, V=30V and i=2A, so:
30=E+2r
Find the Internal Resistance
Now, subtract equation (i) from equation (ii):
‌(30)−(20)=(E+2r)−(E−2r)
‌10=4r
So, r=‌

10

4

=2.5Ω