(a)

The variation in brightness .

Where,

 is the magnitude of brightness of the fainter body.

is the magnitude of brightness of the brighter body.

When compared both sun and moon, sun is brighter than moon.

Magnitude of brightness of the brighter body is .

Magnitude of brightness of the fainted body is .

Substitute and in .

The variation in brightness between the Sun and the full Moon is units.

(b)

Find magnitude brightness of Mercury.

When compared  both Venus and Mercury,  Venus is brighter than Mercury.

The variation in brightness between Mercury and Venus is .

Magnitude of brightness of the brighter body is .

Substitute and in .

Apply logarithm on each side.

Apply power property of logarithm : .

.

Magnitude brightness of mercury is .

(c)

Find magnitude brightness of Jupiter.

When Compared both Jupiter and Neptune, Jupiter is brighter than Neptune.

The variation in brightness between Neptune and Jupiter is .

Magnitude of brightness of the fainted body is .

Substitute and in .

Apply logarithm on each side.

Apply power property of logarithm : .

.

Magnitude brightness of Jupiter is .

(a)  The variation in brightness between the Sun and the full Moon is .

(b)  Magnitude brightness of mercury is .

(c)  Magnitude brightness of Jupiter is .