Answer:
a)
, b)
, c) 
Explanation:
a) The net flux through the cube is:


b) The flux through the right face is:


c) The flux through the left face is:


When smoke particles pass between the source of radiation and the detector the drop in radiation will be sufficient to tigger the alarm. <span />
Answer: Eclipse
Explanation: A lunar eclipse occurs when the full moon moves through the shadow of the Earth. This can only happen when the Earth is between the Moon and the Sun and all three are lined up in the same plane, called the ecliptic. The ecliptic is the plane of Earth's orbit around the Sun.
The answer depends heavily on what 'objects' you're talking about.
True I hope this helps you out