Answer:
1.
Firstly removing off one strip and it leaves electrons behind, so the strip becomes positively charged.
2. The roll however is not negatively charged because it is "earthed " by the hand holding it, thus excess negatives repel each other away through the hand.
3.Tearing off the next strip and once more it leaves electrons behind, the new strip is also positively charged and will repel the first strip.
4. Then, tear two strips apart and one will leave electrons behind on the other. Meaning that one strip is positive and the other is negative and they will attract each other.
When the iron bar is placed within the coils of a solenoid it then becomes a magnet.
Answer:
Maximum distance of image from mirror is equal to focal length of the mirror
Explanation:
As we know by the equation of mirror we have

here we know for convex mirror
object position is always negative as it will be placed behind the mirror always
while the focal length of the convex mirror is always taken positive
So here we have


so here maximum value of image distance is equal to focal length of the mirror