All Free Everyday Science MCQs with Answers

81. Comets are made mostly of ______________?

• A. Ice and dust
• B. Dust and lights
• C. Ice, dust and lights
• D. All of the above

Explanation: A comet's nucleus is mainly a mixture of ice and dust, with frozen gases and rocky grains also present. “Lights” is not a material from which comets are made.

82. Comets are made mostly of ice and dust. As comets get close to the sun, they start to "melt" and release what?

• A. Steam and dust
• B. Gas and dust
• C. Steam, gas and dust
• D. None of the above

Explanation: Near the Sun, cometary ices sublimate directly into gas, carrying dust away from the surface. The visible release is therefore gas and dust rather than ordinary steam alone.

83. The moon's surface has been explored by how many astronauts?

• A. 10
• B. 11
• C. 12
• D. 13

Explanation: Twelve astronauts walked on the Moon during the six successful Apollo landing missions, from Apollo 11 through Apollo 17. Several other astronauts orbited the Moon but did not land.

84. The moon has a large, circular basin called _____________?

• A. the Simerian Basin
• B. the Inbrium Basin
• C. the Imbrium Basin
• D. Black Bowl Basin

Explanation: The Imbrium Basin is the large impact basin associated with the Moon's Mare Imbrium. “Inbrium” is a common spelling trap caused by misplacing the first consonant.

85. Which one of the following is true?

• A. The moon has both atmosphere and magnetic field
• B. The moon has no atmosphere or magnetic field
• C. The moon has atmosphere but no magnetic field
• D. The moon has magnetic field but no atmosphere

Explanation: The Moon has no substantial atmosphere and no global magnetic field, so basic astronomy texts describe it this way. It does possess an extremely thin exosphere and small localized magnetic anomalies, but these are not treated as a normal atmosphere or planetary field.

86. The moon's surface temperature varies from about ________ to _________ ?

• A. - 173 degrees Celsius at night to 127 degrees Celsius during the day
• B. - 172 degrees Celsius at night to 172 degrees Celsius during the day
• C. Remains constant during day and night
• D. - 170 degrees Celsius at night to 107 degrees Celsius during the day

Explanation: With virtually no atmosphere to distribute heat, the lunar surface becomes extremely cold at night and very hot in daylight, roughly from −173°C to 127°C. This large contrast is much greater than on Earth.

87. Which of the following was first to be discovered in the chromospheres of the sun?

• A. Krypton
• B. Xenon
• C. Neon
• D. Helium

Explanation: Helium was first identified through a spectral line in the Sun's chromosphere before it was discovered on Earth. Its name comes from Helios, the Greek name for the Sun.

88. When in the part of its orbit closest to the Sun, Pluto has an atmosphere of nitrogen and methane similar to Triton's, but what happens when it is farther from the Sun ?

• A. These gases are not present
• B. These gases are like plasma
• C. These gases are frozen
• D. These gases are volatile

Explanation: As Pluto moves farther from the Sun, its surface becomes colder and nitrogen and methane condense and freeze onto the surface. This causes much of its temporary atmosphere to collapse.

89. Titan, a moon of __________ , and Triton, a moon of _________ , have atmospheres mainly of _________.

• A. Saturn, Jupiter, Hydrogen
• B. Uranus, Neptune, Nitrogen
• C. Saturn, Neptune, Nitrogen
• D. Mars, Venus, Hydrogen

Explanation: Titan is Saturn's moon and Triton is Neptune's moon; both have nitrogen-dominated atmospheres. Jupiter and Uranus are therefore incorrect planet pairings in the other options.

90. The planet retains an atmosphere when?

• A. Gravity is low and temperature of atmosphere is great
• B. Gravity and temperature both are great
• C. Gravity and temperature both are constant
• D. Gravity is great and temperature of atmosphere is low

Explanation: A planet retains an atmosphere more effectively when its gravity is strong enough to hold gas particles and the atmospheric temperature is low enough to limit their speed. Weak gravity and high temperature allow gases to escape into space.