Webcam is a device used to capture images, audio and videos. Webcam are either inbuilt or can be externally attached with the laptop or the computer. The most common application of a webcam is video chat, video recording, image capturing. A webcam generally consist of a lens, an image and sound sensors, electronic circuitry to process the data and send it to PC. A variety of webcams with different features are available in the markets. Depending on the features and quality, the technologies used and the prices vary. However the basic function remains the same.
The webcam attached on the laptop is shown in the image above. You can see an optical lens to capture the images/videos and a small hole to capture sound. The bottom part of the body consists of a plastic casing which provides support to the webcam and a mechanism to fix the webcam on the top of the laptop.