The mirror formula for curved mirrors is:

where
f is the focal length of the mirror

is the distance of the object from the mirror

is the distance of the image from the mirror
The sign convention that should be used in order to find the correct values is the following:
-

: positive if the mirror is concave, negative if the mirror is convex
-

: positive if the image is real (located on the same side of the object), negative if it is virtual (located on the opposite side of the mirror)
Explanation:
The given data is as follows.
q = 6.0 nC = 
inner radius (r) = 1.0 cm = 0.01 m (as 1 cm = 100 m)
So, there will be same charge on the inner surface as the charge enclosed with an opposite sign.
Formula to calculate the charge density is as follows.
.......... (1)
Since, area of the sphere is as follows.
A =
........... (2)
Hence, substituting equation (2) in equation (1) as follows.

=
= 
or, = 4.77 
Thus, we can conclude that the resulting charge density on the inner surface of the conducting sphere is 4.77
.
Answer:
my mind cant comprehend a shing word u just said
Explanation:
Before going to answer this question first we have to know the fundamental principle of magnetism.
A magnet have two poles .The important characteristic of a magnet is that like poles will repel each other while unlike poles will attract each other.
Through this concept the question can be answered as explained below-
A-As per first option the side of magnet A is repelled by the south pole of magnet B. Hence the pole of a must be south .It can't be north as it will lead to attraction.
B-The side of magnet A is repelled by the north pole of magnet B. Hence the side of A must be north pole.It can't be a south pole.
C-The side of magnet A is attracted by the south pole of magnet B .Hence the side of magnet A must be north.Hence this is right
D-The side of magnet A is attracted by the north pole of magnet B. Hence the side of A must south.It can't be north as it will lead to repulsion.
Hence the option C is right.
A developing story hope it helped