1.
What is the SI unit (International System of Units) of speed?
Correct Answer
A. M/s
Explanation
The SI unit of speed is meters per second (m/s). This unit represents the distance traveled in meters divided by the time elapsed in seconds. Meters per second (m/s) is commonly used in scientific and engineering calculations to measure the rate at which an object or person is moving. The m/s unit allows for precise and consistent measurements, making it the standard unit for speed in the International System of Units (SI).
2.
What is the process by which plants make their food?
Correct Answer
B. Photosynthesis
Explanation
Photosynthesis is the process by which plants convert water, and carbon dioxide into glucose and oxygen by fixing or absorbing sunlight. During photosynthesis, plants use chlorophyll in their leaves to capture solar energy, which is then used to convert water and carbon dioxide into glucose. This process is essential for plants to produce their own food and release oxygen into the atmosphere. Transpiration is the process of water movement through a plant. Translocation refers to the movement of sugars and other nutrients within a plant. Perspiration is the process of sweating in animals.
3.
Plants do not breathe.
Correct Answer
B. False
Explanation
Plants do not have lungs like animals, but they also perform respiration. Through tiny openings called stomata, plants take in carbon dioxide and release oxygen. This process is essential for their survival, as it provides them with the energy they need to grow and carry out other metabolic activities.
4.
From where does a solar cell receive its energy?
Correct Answer
A. Sunlight
Explanation
A solar cell receives energy from sunlight. Sunlight is the primary source of energy for solar cells because they convert solar energy into electricity via the photovoltaic effect. However, solar cells can also generate electricity from artificial light sources such as incandescent or fluorescent bulbs. These artificial light sources emit photons that can be absorbed by the solar cell's semiconductor material, allowing for the generation of electricity.
5.
How many planets are there in our solar system?
Correct Answer
B. 8
Explanation
Our solar system consists of eight planets. These planets, in order from the Sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto, once considered the ninth planet, was reclassified as a dwarf planet by the International Astronomical Union in 2006. Each planet has unique characteristics and orbits the Sun, forming the planetary system that we observe today.
6.
What is the moon?
Correct Answer
A. Satellite
Explanation
The moon is considered a satellite because it orbits around a larger celestial body, which in this case is Earth. Satellites are objects that revolve around a planet or a star. The moon fits this definition as it maintains a consistent orbit around our planet. The moon is not a plant: it does not possess any characteristics of a living organism. While the moon is round, this is not the primary reason for it being classified as a satellite; objects that are not spherical and orbit around planets, such as the Martian moons Phobos and Deimos, are considered satellites. Lastly, it is not a glowing object because its illumination is caused by the reflection of sunlight rather than its own light source.
7.
What is the movement of the earth on its axis called?
Correct Answer
B. Rotation
Explanation
Rotation refers to the circular movement of an object around its axis. In this case, the Earth rotates on its axis and causes day and night. Earth’s rotation takes approximately 24 hours to complete. Revolution refers to the Earth's movement around the Sun, which takes about 365.25 days to complete. Motion and vibration are not specific to the earth's movement on its axis and do not accurately describe this phenomenon.
8.
Walking on the Earth’s moon is as easy as walking on Earth.
Correct Answer
B. False
Explanation
Walking on the Earth’s moon is difficult due to the Moon’s significantly reduced gravity. The Moon has approximately 1/6th of Earth’s gravity, which means that our bodies would feel much lighter. Due to the reduced gravity on the Moon, it would be difficult to maintain balance and stability while walking.
9.
What is the collection of hundreds of millions of stars in a large celestial body called?
Correct Answer
A. Galaxy
Explanation
A galaxy is a collection of hundreds of millions of stars, along with gas, dust, and other smaller celestial bodies, held together by gravity. Galaxies come in various shapes and sizes and are the building blocks of the universe. They can contain billions or even trillions of stars, along with other celestial objects like planets, asteroids, and comets. The term "galaxy" is commonly used to refer to the Milky Way, the galaxy in which our solar system resides, but there are countless other galaxies in the universe, such as Andromeda.
10.
What type of objects can we see through?
Correct Answer
C. Transparent
Explanation
Transparent objects allow light to pass through them with minimal scattering and absorption, making them see-through. This optical clarity means that we can clearly observe objects located on the other side of transparent materials, such as glass or clear plastic, without any obstruction to the view, enhancing visibility and light transmission.
11.
What type of energy is stored in food that we eat?
Correct Answer
C. Chemical Energy
Explanation
The energy stored in the food we eat is known as chemical energy. This type of energy is stored in the bonds of molecules within the food. When we digest food, these chemical bonds are broken down, releasing energy that our bodies use to perform various functions such as movement, growth, and maintaining body temperature. Kinetic energy, thermal energy, and nuclear energy do not describe the stored energy in food.
12.
What causes the different phases of the Moon?
Correct Answer
D. The Moon's position relative to the Earth and Sun.
Explanation
The different phases of the Moon are caused by the changing angles of the Moon, Earth, and Sun as the Moon orbits the Earth. As the Moon moves around the Earth, we see varying portions of its illuminated side, leading to the phases such as new moon, crescent, quarter, gibbous, and full moon.
13.
What is the primary source of energy for the Earth?
Correct Answer
B. Sun
Explanation
The primary source of energy for the Earth is the Sun. The Sun provides light and heat, which are crucial for sustaining life on Earth. Its energy drives photosynthesis in plants, influences weather patterns, and maintains Earth's temperature. Without the Sun, Earth would be too cold and lifeless. The Sun's energy reaches the Earth in the form of electromagnetic radiation, including visible light, infrared, and ultraviolet rays. This energy is absorbed by the Earth's surface and atmosphere, driving various processes like ocean currents, wind patterns, and the water cycle.
14.
What is the process by which water changes from liquid to gas?
Correct Answer
C. Evaporation
Explanation
The process by which water changes from liquid to gas is evaporation. Evaporation occurs when molecules at the surface of the liquid water gain enough energy to break free from the liquid state and become water vapor. This typically happens when water is heated by the Sun, causing the temperature of the liquid to rise. As molecules move faster with increased energy, they escape the liquid phase and enter the atmosphere as vapor. Evaporation is an essential part of the water cycle, contributing to cloud formation and rainfall.
15.
What is the name of the process by which plants release water vapor into the air?
Correct Answer
A. Transpiration
Explanation
Transpiration is the process by which plants release water vapor into the air. This occurs through small openings called stomata on the leaves. As plants absorb water from the soil through their roots, they transport it up through their stems to the leaves. Some of the water is used in photosynthesis, while the rest evaporates through the stomata in a process known as transpiration. Transpiration helps regulate the plant’s temperature, promotes nutrient uptake, and contributes to the water cycle by adding moisture to the atmosphere, which eventually leads to precipitation.