Olympiad Test Level 2: Our Earth and Universe- 1 - Class 7 MCQ

The mantle extends from moho’s
discontinuity to a depth of 2900 km. The upper portion of mantle is called asthenosphere. The crust and uppennost part of mantle are called lithosphere. The lower mantle extends beyond asthenosphere. It is in solid state.

The permanent tilt of the Earth’s axis and the revolution of the Earth in its orbit have several effects on our planet. Let's break down the given options and see which effects are caused by these factors:
I. Deflection of winds and ocean currents:
- The tilt of the Earth's axis causes variations in the angle at which sunlight reaches different parts of the Earth.
- This variation in solar radiation leads to differences in temperature, which in turn creates pressure gradients.
- These pressure gradients cause the movement of air masses, resulting in winds.
- Similarly, the uneven heating of the Earth's surface also leads to the movement of ocean currents.
II. Differences in time between places on different meridians:
- The Earth is divided into time zones based on the rotation of the Earth on its axis.
- As the Earth rotates, different parts of the planet experience daylight and darkness at different times.
- The time difference between places on different meridians is primarily caused by the rotation of the Earth.
III. Varying length of day and night at different times of the year:
- The tilt of the Earth's axis causes the angle at which sunlight reaches different parts of the Earth to change throughout the year.
- This change in angle leads to variations in the length of daylight and darkness at different times of the year.
- During summer, the hemisphere tilted towards the Sun experiences longer days, while the hemisphere tilted away from the Sun experiences shorter days.
IV. Changes in the altitude of the mid-day sun at different times of the year:
- The tilt of the Earth's axis also affects the altitude of the mid-day sun.
- When a hemisphere is tilted towards the Sun, the mid-day sun appears higher in the sky, resulting in a higher altitude.
- Conversely, when a hemisphere is tilted away from the Sun, the mid-day sun appears lower in the sky, resulting in a lower altitude.
Based on the above explanations, we can conclude that the permanent tilt of the Earth's axis and the revolution of the Earth in its orbit cause the following effects:
- Deflection of winds and ocean currents (I)
- Differences in time between places on different meridians (II)
- Varying length of day and night at different times of the year (III)
- Changes in the altitude of the mid-day sun at different times of the year (IV)
Therefore, the correct answer is option A: II, III, and IV.

The correct answer is B: asteroid.
Explanation:
An asteroid is a rocky object that is small in size and revolves around the Sun. Here is a detailed explanation:
- Asteroids:
- Asteroids are rocky objects that are smaller than planets but larger than meteoroids.
- They are composed of various materials such as rock, metal, and sometimes ice.
- Asteroids are irregularly shaped and can range in size from a few meters to hundreds of kilometers in diameter.
- They orbit the Sun in a region called the asteroid belt, which is located between the orbits of Mars and Jupiter.
- Some asteroids can also have their own moons.
- Meteoroids:
- Meteoroids are small rocky or metallic objects that are smaller than asteroids.
- They can range in size from tiny particles to a few meters in diameter.
- Meteoroids are often remnants of asteroids or comets that have broken apart.
- They travel through space and can enter Earth's atmosphere.
- Meteors:
- When a meteoroid enters Earth's atmosphere, it heats up and produces a streak of light called a meteor.
- Meteors, also known as shooting stars, can be seen as bright, fast-moving objects in the night sky.
- Most meteors burn up completely before reaching the Earth's surface.
- Meteorites:
- If a meteoroid survives its journey through the Earth's atmosphere and lands on the Earth's surface, it is called a meteorite.
- Meteorites can provide valuable information about the composition and history of our solar system.
In conclusion, a small rocky object that revolves around the Sun is called an asteroid.

Big Bang theory explains origin of Universe

Answer:Nuclear waste

 

Explanation:

 

Nuclear waste is the kind of waste that lasts the longest in the environment. Here's why:

 

Therefore, nuclear waste is the kind of waste that lasts the longest in the environment and requires careful management to minimize its harmful effects.

• Radioactive decay: Nuclear waste contains radioactive materials that undergo radioactive decay, which can take thousands of years.


• Long half-life: The radioactive isotopes in nuclear waste have long half-lives, meaning it takes a significant amount of time for them to decay to a harmless state.


• Persistent impact: Nuclear waste poses serious health and environmental risks due to its long-lasting radioactive properties. It can contaminate soil, water, and air, impacting ecosystems and human health.


• Secure storage: Proper disposal and storage of nuclear waste are crucial to minimize its long-term impact. Specialized facilities are required to store nuclear waste safely.

 

Explanation:
The incorrect statement regarding equinox is:
C: In the Southern hemisphere, the vernal equinox occurs in March while the autumnal equinox occurs in September.
Here's a detailed explanation for each statement:
A: Equinox is the moment when the plane of Earth's equator passes through the center of the Sun.
- This statement is correct. The equinox occurs twice a year, around March 20th and September 22nd, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, resulting in equal day and night lengths.
B: During equinox, the Northern and Southern hemispheres are equally illuminated.
- This statement is also correct. During the equinox, the Sun shines directly on the equator, and as a result, both the Northern and Southern hemispheres receive an equal amount of sunlight. This leads to approximately equal day and night lengths worldwide.
C: In the Southern hemisphere, the vernal equinox occurs in March while the autumnal equinox occurs in September.
- This statement is incorrect. In the Southern hemisphere, the vernal equinox actually occurs in September, marking the start of spring, while the autumnal equinox occurs in March, marking the start of autumn.
D: None of these
- This option is not applicable as one of the statements is incorrect.
Therefore, the correct answer is C: In the Southern hemisphere, the vernal equinox occurs in March while the autumnal equinox occurs in September.

The correct ascending order of distance of planets from the sun is:
- Mars
- Earth
- Jupiter
- Saturn
Explanation:
The distance of planets from the sun is determined by their respective orbits. The closer a planet is to the sun, the lower its distance value. Based on this, the correct ascending order of distance for the given planets is as follows:
- Mars: Mars is the fourth planet from the sun and is located between Earth and Jupiter. It is further away from the sun compared to Earth, Jupiter, and Saturn.
- Earth: Earth is the third planet from the sun and is located between Mars and Jupiter. It is closer to the sun compared to Mars but further away compared to Jupiter and Saturn.
- Jupiter: Jupiter is the fifth planet from the sun and is located between Mars and Saturn. It is further away from the sun compared to Mars and Earth but closer compared to Saturn.
- Saturn: Saturn is the sixth planet from the sun and is located after Jupiter. It is the furthest planet from the sun among the given options.
Therefore, the correct ascending order of distance for the given planets from the sun is Mars, Earth, Jupiter, and Saturn.

The majority of asteroids are found between the orbits of Mars and Jupiter.
Reasoning:
- The region between Mars and Jupiter is known as the asteroid belt. It is a region of space that contains a large number of small rocky objects, called asteroids.
- The asteroid belt is located approximately 2.2 to 3.2 astronomical units (AU) from the Sun. One AU is the average distance between the Earth and the Sun.
- The asteroid belt is situated within the inner solar system, between the orbits of Mars and Jupiter.
- The gravitational forces exerted by Jupiter's massive size prevent the asteroids from forming into a planet.
- The asteroids in the asteroid belt vary in size, ranging from small rocky debris to larger objects several hundred kilometers in diameter.
- The largest asteroid in the asteroid belt is Ceres, which is classified as a dwarf planet.
- The presence of the asteroid belt poses a potential hazard for spacecraft traveling through the inner solar system, as the asteroids can pose a collision risk.
Conclusion:
Based on the above reasoning, the majority of asteroids are found between the orbits of Mars and Jupiter, in the region known as the asteroid belt.

The planet appears to be yellowish is Saturn.

John Glenn is the correct answer.
Explanation:
- John Glenn was the first American to orbit the Earth.
- He was also the oldest person to fly in space, as he returned to space at the age of 77 on the Space Shuttle Discovery in 1998.
- Glenn was one of the members of the Mercury Seven, a group of seven astronauts selected for Project Mercury, the first human spaceflight program of the United States.
- The Mercury Seven astronauts flew on the Mercury spacecraft, which was the first crewed spacecraft of the United States.
- The other options given are not correct:
- Ed White was an American astronaut who became the first American to walk in space during the Gemini 4 mission.
- Alexei Leonov was a Soviet cosmonaut who became the first person to conduct a spacewalk during the Voskhod 2 mission.
- Alan Shepard was the first American to travel into space and the fifth person to go to space overall, but he did not orbit the Earth.
Therefore, the correct answer is John Glenn.