During the first quarter phase how much of the moon appears illuminated

Half of the moon or 50%

Explanation:

The first quarter phase of the moon is when the Sun illuminates the half part of the moon while the other half rest in darkness.

In the first quarter phase of the moon, the illumination on the moon surface keeps on rising.

When the new moon appear, there is no illumination while the illumination is 100 % on Full moon.

For the phases of crescent moon, it ranges from 0 - 50% and then for gibbous phase, the range of the illumination is from 50-100%from new

50%

Explanation:

The first quarter of the moon is often called the half moon. It occurs when half moon is illuminated by the sun and other half of the moon remains in the darkness. When we observe 1st quarter of moon the amount of moon being illuminated keeps increasing and this increasingly illuminated moon is called waxing.