I'm trying to understand why this simple circuit below works the way does: As it gets darker over the photoresistor (RP) the LED gets brighter. 

I'm trying to understand it by following the path the electricity takes through it (from - to +). 

My theory is that when the room is bright, the electricity flows through the photoresistor and never actually gets to the transistor's emitter (so the LED stays off). When the room is dark, the photoresistor has near infinite resistance and thus the electricity is forced to go through the transistor (so the transistor is activated and the LED goes on). 

[![enter image description here](https://i.stack.imgur.com/ywK9c.jpg)](https://i.stack.imgur.com/ywK9c.jpg)