Question

Brightest planet in the night sky:
A) Jupiter
B) Venus
C) Earth
D) Mars

Answer 1

Hint
Because planets are not self luminous, that is they don’t emit light . They shine because they reflect back the light they receive from the Sun. Considering the brightness it depends on several factors like how far the planet is from , what are the major elements present on the surface of the planet . Consider a metallic ball which is placed a little far from a lantern and another rubber ball which is placed near to the lantern when we try to compare the brightness of these two balls the metallic ball will shine although it is far.

Complete step by step solution
As we planets don’t produce their own light they shine because they bounce back the light they receive from their neighbouring stars.
In case our solar system Mercury is closest to the sun and then Venus and then Earth and then Mars and Jupiter (considering given options). Now analyzing different gases present on these planets and observing how close they form the Sun.
Considering composition of planets:
Jupiter: Its atmosphere is made up of mostly hydrogen gas and helium gas, like the sun. The planet is covered in thick red, brown, yellow and white clouds.
Venus: It is still the hottest. It has a thick atmosphere full of the greenhouse gas carbon dioxide and clouds made of sulfuric acid. The atmosphere traps heat. It's so hot on Venus, metals like lead would be puddles of melted liquid.
Mars: It is almost like Earth, it has rocks and mud and in gases it contains Carbon-di-oxide, Nitrogen, Argon, Oxygen.
Earth: As we all know what is the composition of Earth. Water and rocks. In gases Nitrogen, Oxygen are main.
From space, Venus is bright white because it is covered with clouds that reflect and scattered sunlight. At the surface, the rocks are different shades of grey, like rocks on Earth, but due to the thick atmosphere that filters the sunlight so that everything would look orange if you were standing on Venus.
These are some reasons why Venus is the brightest in the night sky.
Hence, Option (B) is correct.

Note
The atmosphere of Venus is very thick and is about 90 times bigger than Earth's atmosphere. It is mostly carbon dioxide gas (approx.. 96%), with some nitrogen (approx. 3%) and a very small amount of water vapor (approx. 0.003%). Venus also has a thick layer of sulfuric acid clouds. The sulfur in the clouds gives Venus its yellowish appearance. The clouds in Venus's atmosphere also move very fast, reaching speeds of 350 km per hour.