A Light Dependent Resistor (LDR) is a type of resistor that changes its resistance based on the amount of light it receives. When light falls on the LDR, its resistance decreases, allowing more electric current to flow through it. This property makes LDRs useful in various applications, such as light sensors and automatic lighting systems. LDRs are commonly made from materials like cadmium sulfide, which are sensitive to light. They are often used in devices like streetlights, which turn on automatically at dusk, and in solar garden lights, where they help conserve energy by activating only when it’s dark.