Consider the network shown in initially, the switch `S_(1)` is closed and `S_(2)` is open.

a. Calculate `V_(A) - V_(B).`
b. When `S_(2)` is also closed, what is `V_(A) - V_(B)`
i. just after closing , ii. After long time.

Explanation

`S_(1)` is closed, `S_(2)` is open. `V_(M) = V_(A) = (1xx24)/(1+5) = 4V, V_(M) - V_(B)= (3xx24)/(3 +3) = 12V `
`V_(A) - V_(B) = 8V`
i. Just after closing `S_(2)` A and B will come to the same
potential, so `V_(A) - V_(B) = 0.`
ii. After a long time, no current will flow through AB, so
`V_(A)- V_(B) = 8 V.`