Logic gates are used in:A. LDRs B. DC circuitsC. Analogue circuits D. House safety

Logic gates are fundamental building blocks of digital circuits. They are used to perform logical operations on one or more binary inputs to produce a single binary output.

1. Explanation of Logic Gates: Logic gates function based on the principles of boolean algebra. The most common types include AND, OR, NOT, NAND, NOR, XOR, and XNOR gates. They are predominantly used in digital electronics.

2. Application Areas:

   • Options Analysis:
     • A. LDRs (Light Dependent Resistors): While LDRs are used in circuits, they don't utilize logic gates themselves.
     • B. DC Circuits: Direct Current (DC) circuits can use logic gates, especially in digital systems powered by DC sources.
     • C. Analogue Circuits: Analogue circuits operate on continuous signals and typically do not employ logic gates.
     • D. House Safety: Logic gates could be used in house safety systems (like alarms), but in broader terms, it's a less direct application.

3. Conclusion: Among the options, B. DC circuits is the most relevant answer, although logic gates can also be used indirectly in house safety systems.

Thus, while options B and D demonstrate applications, B is the most appropriate for the context of logic gates.