It isn't.
it may be activated by a light sensitve photocell. if the cell detects light, it doesn't come on, that way it conserves the solar energy until it's dark, and you need the light to activate.
The terminator
The moon reflects the suns light and things on the eart do notreflect it because it is at an angle in which the light does not reach earth. So if the light falls on the earth at night there would be light but because it not reflect it on earth it is dark at night.
The moon never produces light on it's own, it's rocks reflect sunlight - the "light side" is the visible side which we see from earth. The "dark side" is usually invisible to viewers on Earth, except during a solar eclipse or if light reflecting off the Earth briefly illuminates the dark side (earthshine).
Yes absolutely. The moon is at the back of the earth so the earth becomes dark.
outside
You match the rings with the bolts. Look carefully at the bolts, there is an inside and outside color... dark or light. If the bolt in the corresponding color is dark on the inside and dark on the outside, then tap the ring on the door until it looks the same as the bolt. Do this with all four bolt-ring combinations, and the doors will open. Just in case it is hard to tell: Upper left bolt is Dark-inside, Dark outside Upper right is Light-inside, Light outside Lower left is Light-inside, Dark outside Lower Right is Dark-inside, Light outside.
You match the rings with the bolts. Look carefully at the bolts, there is an inside and outside color... dark or light. If the bolt in the corresponding color is dark on the inside and dark on the outside, then tap the ring on the door until it looks the same as the bolt. Do this with all four bolt-ring combinations, and the doors will open. Just in case it is hard to tell: Upper left bolt is Dark-inside, Dark outside Upper right is Light-inside, Light outside Lower left is Light-inside, Dark outside Lower Right is Dark-inside, Light outside.
because the sun is blocked out by the earth.
It is dark in california baby
When the Earth rotates, the light from the sun moves in different spots on earth. When the sun's light isn't shining in your country, it gets dark. This is nighttime. When the sun comes back, there's light outside. This is daytime. That's how days were created.