Introduction:
An ideal switch is a theoretical concept used in physics and electrical engineering to simplify the analysis of circuits. It is an electronic component that can control the flow of electric current by either allowing it to pass through (ON state) or blocking it (OFF state). In an ideal switch, certain characteristics are expected.

Zero Resistance when OFF:
- When the switch is in the OFF state, it is expected to have zero resistance. This means that no current should be able to flow through the switch when it is open.
- Zero resistance ensures that there is no voltage drop across the switch in the OFF state, allowing the circuit to remain unaffected by the presence of the switch.
- It simplifies circuit analysis because it eliminates the need to consider any resistance associated with the switch itself.

Infinite Resistance when ON:
- When the switch is in the ON state, it is expected to have infinite resistance. This implies that the switch acts as an open circuit, completely blocking the flow of current.
- Infinite resistance ensures that no current can pass through the switch in the ON state, allowing the circuit to remain unaffected by the presence of the switch.
- Similar to the zero resistance when OFF, infinite resistance when ON simplifies circuit analysis by eliminating the need to consider any resistance associated with the switch itself.

Combining Zero and Infinite Resistance:
- By combining zero resistance when OFF and infinite resistance when ON, an ideal switch provides a clear distinction between the two states.
- When the switch is ON, the circuit behaves as if the switch is not present at all, and when it is OFF, the circuit behaves as if there is no resistance in the switch.
- This simplification allows for easier analysis and calculation of circuit parameters such as current, voltage, and power.

In conclusion, an ideal switch has zero resistance when OFF and infinite resistance when ON. These characteristics simplify circuit analysis by eliminating the need to consider resistance associated with the switch and ensuring that the circuit remains unaffected by the presence of the switch in both states.