I'm Really Worried I Have Upset My...
Family & Relationships1 min ago
No best answer has yet been selected by montyy. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.Montyy - using the internet to research answers to homework questions is legitimate, and can result in you learning a lot more than just that answer, and I'm sure your teacher has no problems with that.
But what you're doing here is asking others to do your research for you.
Are you sure you don't know what a sensor is?
Homeworks a pain, but if you're going to do it, then do it yourself. One day you'll thank me. (OK, you won't)