A Level Physics Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Study for the A Level Physics Exam. Our quiz features flashcards and multiple choice questions, each with hints and explanations. Prepare thoroughly!

Start Multiple Choice Practice Test
Start Flash Cards

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

What occurs to the resistance of an LDR as light intensity increases?

  1. Resistance increases

  2. Resistance decreases

  3. Resistance remains constant

  4. Resistance fluctuates rapidly

The correct answer is: Resistance decreases

As light intensity increases, the resistance of a Light Dependent Resistor (LDR) decreases. LDRs are made from semiconductor materials that are sensitive to light. When light photons strike the material, they excite the electrons, allowing them to flow more freely and increasing the material's conductivity. This results in a lower resistance. In practical applications, this property allows LDRs to be used in various light-sensing circuits, such as automatic lighting systems. The decrease in resistance as light intensity rises is fundamental to how LDRs function, making them effective for detecting changes in light levels.

More Questions Like This