Question

A thin square sheet of metal of uniform thickness and of side 'a' has a resistance 4ohm measured between opposite edges. it is connected to another sheet if same metal of same thickness but of lenght 2a and width a/2. what 8s the resistance between edges p and q​

Answer 1

$\frac{ \alpha l}{a} = r \\ \frac{ \alpha a}{ {a}^{2} } = 4 \\ \alpha = 4a$

now

$\frac{4a \times 2a}{2a \times \frac{a}{2} } = new \: r \\ new \: r \: = 8ohms$

both are in series

so resultant is 12 ohm