Q.Two switches connected in series in a circuit are represented symbolically by:

A series connection carries current only when both switches are closed, matching conjunction.

In a series connection the two switches lie one after the other on a single path, so current flows only when both are closed. In truth-value terms the circuit is "on" only when both $p$ and $q$ are $T$ — precisely the behaviour of the conjunction $p \wedge q$. Hence the answer is (b).

Checking the options. (a) $p \vee q$ is the parallel connection (current flows if at least one is closed) — the opposite arrangement. (c) $\sim p$ represents a single complementary switch, not two in series. (d) $p \rightarrow q$ is a conditional, which does not model a physical two-switch connection. Only (b) matches a series circuit. …

The usual confusion is swapping series and parallel. Series (single path, both must be closed) is conjunction (and); parallel (bra …