Answer:
1.C
2.D
3.B
4.D
Step-by-step explanation:
1. The orbit on which moon revolve around earth has a perigee point which is the nearest point to earth while apogee is the farthest point to planet earth.
A penumbral is a region in which occluding body obscure a portion of light. It has no relation with the moon's orbit. Also an eclipse is a phase based on position of moon with respect to earth and sun
Hence, option C is correct
2. Gamma rays are extremely powerful and energetic as they are produced as a result of radiation and hence it is very difficult to focus them on normal lenses which are designed to focus only visible light. They interact with the matter of the focusing surface and destroys them selves.
Hence, option D is correct
3. Corona is the outer surface of stars that extends to millions of kilometers into the space. Sun being a star has corona at its outer layer which is visible only during
total solar eclipse. Hence option B is correct
4. When the gravitational force of moon attracts the water on earth, it presume a rising and falling form that is termed as tides.
Hence option D is correct