Final answer:
Sketchpad was a program that allowed users to interact with a user interface using a light pen. The light pen emitted a magnetic field that was detected by wires underneath the screen, allowing the user to draw or interact with the computer.
Step-by-step explanation:
Sketchpad was a program that allowed users to interact with a user interface (UI) using a light pen.
The light pen was a device that could be used to draw digital images or interact with the computer screen.
It worked by emitting a tiny magnetic field from the tip, which was detected by tiny wires underneath the screen.
As the pen moved across the screen, the changing magnetic field translated into an induced emf that was converted into the user's input.