Switch fundamentals — normally open (NO) push button: Under what condition can current flow through a normally open push button switch in a simple series circuit?

Introduction / Context:
Understanding switch contact states is essential for troubleshooting and designing basic control circuits. A normally open (NO) push button is used for momentary activation—think doorbells, start buttons, and user inputs to logic systems.

Given Data / Assumptions:

• Switch type: normally open (NO) push button.
• Simple series circuit with a power source and a load.
• Ideal contacts: open = infinite resistance (no current), closed = low resistance (current allowed).

Concept / Approach:
By definition, an NO contact remains open in its rest state. Pressing the actuator mechanically closes the contacts, completing the circuit path so current can flow. Releasing the button opens the contacts again, breaking the circuit and stopping current.

Step-by-Step Solution:
Rest state: NO contact is open → circuit open → current = 0.Press button: contacts close → circuit completed → load current flows.Release button: contacts open → circuit broken → current stops.

Verification / Alternative check:
Compare with a normally closed (NC) push button: NC passes current at rest and interrupts when pressed. This contrast validates the NO behavior described.

Why Other Options Are Wrong:
(b) and (c) state “open” permits current; incorrect. (d) Reasserts the “open” condition and remains false even with a supply. (e) Invalid because a correct choice exists.

Common Pitfalls:
Confusing NO with NC; assuming indicator lights or control logic invert the meaning; overlooking wiring errors that can mask intended behavior.

Final Answer:
Only while you are pressing the button (contacts closed).