You can often see the entire "near side" of the Moon, because even though the sunlit half is very bright, the other part is dimly lit by reflected Earthlight.
However, the official answer to your question is probably "one quarter". You can only see one-half of the Moon, and only half of that is lit up by the Sun.
When the moon appears half lit, you are seeing exactly half of its surface. Half of the moon is illuminated by the sun, while the other half is in shadow. This phase is known as the first quarter when the moon is waxing, and the third quarter when the moon is waning.
A half moon appears when only half of the moon's illuminated side is visible from Earth. This occurs when the moon is at a 90-degree angle relative to the Earth and the sun, known as the first quarter or third quarter moon.
In that case, you would also see a half moon if you could see the moon at all. The moon is in the same phase for everywhere on Earth, so if you can see it at all, you're seeing it in the same phase that anyone else on Earth is seeing.
Nothing happens to the other side of the Moon in half moon days. The reason we do not see the whole Moon is because only half of it is reflecting the light from the Sun.
Assuming you're asking how often a "half moon" appears, a half moon (First or Third Quarter moon) will usually occur every 14-15 days (half a lunar month).
point E is when it clears from a whole moon to a half moon.
If you are on the moon at the time of "New Moon", and you are facing the earth, you see a "Full Earth". If you stay up there a while, and call your partner on earth every day, and you describe to each other what you're seeing, you'll notice something very interesting: The part of the moon that HE sees, plus the part of the earth that YOU see, always adds up to a complete circle of illumination. Each of you sees the part of the circle that the other one is missing.
First quarter and last quarter appear as a half moon. about halfway down this page are some pictures: http://www.calculatorcat.com/moon_phases/moon_phases.phtml
At the time of the "First Quarter" and "Third Quarter" phases, the moon appears half-illuminated. These occasions are roughly 7 days and 21 days after New Moon respectively, and Full Moon occurs at the time exactly midway between them. Note: Both phases are easily visible in the daytime. First Quarter rises in the east around Noon, and Third Quarter sets in the west around Noon.
The moon in the days before and after a full moon appear as a gibbous moon. A gibbous moon is anything between a full moon and a half moon.
No. When you see the whole sun-lit side, you call it a "Full Moon".
The phase of the Moon during which more than half, but less than all, of the visible hemisphere of the Moon is illuminated by sunlight. A gibbous moon is between a full moon and a half moon, or between a half moon and a full moon. There can be two gibbous moons: waxing and waning. " A gibbous moon is one of the phases of the Moon when the size of the illuminated portion is greater than half but not a full Moon. The period between a first quarter moon and a full moon is known as a waxing gibbous moon, because the illuminated region of the Moon is increasing from day to day. After it becomes a full moon, but hasn't reached the last quarter, the Moon is called a waning gibbous moon."