D; solar system, because the planets are inside it.
        
                    
             
        
        
        
1) Focal length
We can find the focal length of the mirror by using the mirror equation:

 (1)
where 
f is the focal length

 is the distance of the object from the mirror

 is the distance of the image from the mirror
In this case, 

, while 

 (the distance of the image should be taken as negative, because the image is to the right (behind) of the mirror, so it is virtual). If we use these data inside (1), we find the focal length of the mirror:

from which we find

2) The mirror is convex: in fact, for the sign convention, a concave mirror has positive focal length while a convex mirror has negative focal length. In this case, the focal length is negative, so the mirror is convex.
3) The image is virtual, because it is behind the mirror and in fact we have taken its distance from the mirror as negative.
4) The radius of curvature of a mirror is twice its focal length, so for the mirror in our problem the radius of curvature is:
 
        
             
        
        
        
Answer:
it is 3
Explanation:
because the crack will be open for the magma to come out
 
        
                    
             
        
        
        
The June solstice in the Northern hemisphere is the summer solstice. The June Solstice in the Southern hemisphere is the winter solstice. The summer solstice is equivalent to the longest day while the winter solstice is equivalent to the shortest day. Therefore on the local sky, when is the June solstice we have have the longest day (longest path of sun in the sky) in the Northern hemisphere and the shortest day (shortest path of sun in the sky) in the Southern hemisphere.
        
             
        
        
        
Answer:
distance between both oasis ( 1 and 2) is  27.83 Km
Explanation: 
let d is the distance between oasis1 and oasis 2
from figure
OC  = 25cos 30 
OE = 25sin30
OE = CD
Therefore BC =  30-25sin30
distance between both oasis ( 1 and 2) is calculated by using phytogoras theorem
in

PUTTING ALL VALUE IN ABOVE EQUATION


d = 27.83 Km
distance between both oasis ( 1 and 2) is  27.83 Km