A light bulb looks dimmer the further away it is because

Most people are near sighted. More light is absorbed by gas in between the bulb and the observer. The same number of photons from the light bulb are spread out over a larger area. Of the Doppler shift effect. Light gets fainter with age.

Walking into your basement one night, you notice you can see only 10 feet with your trusty 50 Watt flashlight. How strong must your flashlight be in order to see the full 20 feet of your basement?

25 Watts 50 Watts 100 Watts 200 Watts 20 feet is too far to see with any flashlight!

While waiting for your bus you see in the distance the familiar glare of its headlights. With your handy light meter you measure the intensity of its light as 10 lumen. After 10 seconds you measure the intensity at 20 lumen. What can you infer about the bus during that 10 second interval?

The bus moved half the distance to you in those 10 seconds. The bus was accelerating during those 10 seconds. The bus was decelerating during those 10 seconds. The bus moved less than half the distance to you in those 10 seconds. The bus moved more than half the distance to you in those 10 seconds.