遮る and 隔てる: blocked light and separated rooms
Compare clouds blocking moonlight with a wall separating two rooms. Identify what is blocked and which spaces are divided without assuming complete light or sound insulation.
遮る: clouds blocking moonlight
遮る（さえぎる） means to block or interrupt. 「厚い雲が月の光を遮っている。」 describes thick clouds blocking the moonlight. 月の光 is what is blocked, and 厚い雲 is what blocks it.
遮っている presents the ongoing state of blocking the light. Read light as the affected target, but do not infer that no moonlight passes through or that the surroundings have become completely dark. The sentence does not specify that degree of blockage.
隔てる: a wall between two rooms
隔てる（へだてる） means to separate or divide. 「二つの部屋を薄い壁が隔てている。」 describes a thin wall separating two rooms. 二つの部屋 identifies the divided spaces, and 薄い壁 identifies the barrier between them.
隔てている describes the wall's separating relationship. It does not report that a wall was newly built or that all light and sound are blocked. 薄い adds that the wall is thin, without specifying its light-blocking or soundproofing performance.
Identify the affected target or spaces
In the first example, ask what the clouds block: the moonlight. In the second, ask which spaces the wall separates: the two rooms. A single object can contribute to both blocking and separation, depending on the relationship being described.
A wall can separate spaces and block light at the same time. For the wall in this example, however, only separation is stated. The clouds' blocking of light should not be transferred to the wall as a guaranteed property.
Does describing a wall with 隔てる establish that it blocks all light and sound?
Show the answer and why
No. Separating spaces does not by itself establish complete light or sound insulation. A wall can contribute to both separation and blocking, but this wall example states only the relationship between the rooms. Moonlight is the blocked target in the other example.