Explanation:
It is given that,
Radius of curvature of the mirror, R = 1.54 cm
(a) We have to find the focal length of the mirror. The relationship between the focal length and the radius of curvature is given by :

f = focal length of the mirror

f = 0.77 cm
(b) The power of mirror is given by the reciprocal of focal length i.e.
Power, 
P = 1.29 diopters
Hence, this is the required solution.
These balloons will be attracted, as you have shown in the picture, there are two positives, they are not in the same spot. when two of the same poles are put together, they rebel each other, since the two positive poles are not in the same area of the balloon, the balloons will attract each other. I hope this helps :)
Think of it this way:
-- Any time you have something that means (some number) PER UNIT,
it doesn't matter how many units there are on the table or in the bucket,
because that amount doesn't change the (number) PER UNIT.
-- If oranges cost $1 PER POUND, it doesn't matter how many pounds
you buy, the whole bagful is still $1 PER POUND.
-- If a certain salad dressing has 40 calories PER Tablespoon, it doesn't
matter whether you eat a drop of it or drink the whole jar. You still get
40 calories PER Tablespoon.
-- Density means '(mass) PER unit of volume'. Whether you have a tiny
chip of the substance or a whole truckload of it, there's still the same
amount of mass IN EACH unit of volume.
C. FM radio waves is the answer.