You've probably seen someone put a fruit in a brown paper bag and store it in a humid place to ripen it. If storage in a dark place is supportive to the ripening process, then common sense seems to dictate that putting fruit under light would hinder ripening. Unfortunately, it's not quite that simple. While light affects ripe fruit, it does so indirectly.
How Ripening Works
Fruits produce ethylene gas as they mature. This gas is a ripening agent, so exposure to it supports further ripening. However, fruits also need the right temperature and humidity to ripen. Green fruits generally take 2 weeks to ripen in an environment with a temperature of between 65 and 70 degrees Fahrenheit, or 3 to 4 weeks in 55-degree conditions.
Role of Light
Light does not directly contribute to the ripening process and fruits actually don't need any light to ripen. However, light shining on a fruit could increase the temperature in that fruit's path. If the light results in a favorable temperature, the fruit ripens. If your fruit is already ripe, then the effect will be an overly ripe fruit.
A big bowl of ripe fruits on a kitchen counter or table provides visual appeal and welcomes visitors to help themselves. However, if the fruit is in the path of intense light, then the heat produced by the light can cause your fruit to over-ripen quickly. As a result, you'll have to discard them. Thus, if you wish to display fruit, find an out-of-the-way spot in which sunlight or indoor lighting does not touch it.
If you've brought home fruits from the grocery store that are already ripe, the best way to keep them ready to eat for the longest possible is to store them in your refrigerator. On the other hand, some produce, including tomatoes, contain substances that degrade in cold temperatures. In such cases, storage in a cool, dark, dry place is best. If your fruit has not yet fully ripened, place the fruit in a paper bag and place the bag in a pantry or cupboard.