JEE MainPhysicsSemiconductors
In an electrical circuit, three switches A , B , and C are used to control an LED. Switches A and B are connected in parallel to each other. This parallel combination is then connected in series with switch C . Finally, this entire three-switch arrangement is connected in parallel across the LED. A battery and a series resistor are used to power the circuit (the resistor prevents the battery from short-circuiting). T
Options
- AY = (A+B) C
- BY = (A+B) C
- CY = (A B) + C
- DY = A B C
Correct answer
B. Y = (A+B) C
Step-by-step solution
The condition for the switch arrangement to conduct current is that switch C must be closed AND at least one of the switches A or B must be closed. In Boolean algebra, switches in parallel represent the OR operation ( A+B ), and switches in series represent the AND operation ( ). Thus, the Boolean expression for the switch path conducting is (A+B) C . Since the entire switch arrangement is connected in parallel across the LED, it will short-circuit the LED whenever it conducts. When the LED is short-circuited, it d