1.
Which of the following is a conversion from chemical energy to thermal energy?
Correct Answer
D. All of the above.
Explanation
All of the given options involve a conversion from chemical energy to thermal energy. In the first option, burning coal releases the chemical energy stored in it, which is then converted into thermal energy to boil water. In the second option, the digestion of food breaks down the chemical bonds, releasing energy that is used to regulate body temperature. In the third option, burning charcoal converts its chemical energy into thermal energy, which is used for cooking in a barbeque pit. Therefore, all three options involve the conversion of chemical energy to thermal energy.
2.
Which of the following is the best example of increasing an object's potential energy?
Correct Answer
C. Stretching a rubber band
Explanation
Stretching a rubber band is the best example of increasing an object's potential energy because when a rubber band is stretched, work is done to store potential energy in the band. The potential energy is stored in the stretched bonds between the molecules of the rubber band, and when released, this potential energy is converted into kinetic energy as the rubber band returns to its original shape.
3.
An object that has kinetic energy must be...
Correct Answer
B. In motion.
Explanation
An object that has kinetic energy must be in motion because kinetic energy is the energy possessed by an object due to its motion. When an object is in motion, it has the potential to do work and therefore has kinetic energy. If the object is at rest or lifted above the earth's surface, it does not have kinetic energy.
4.
Thermal energy is...
Correct Answer
A. Kinetic.
Explanation
Thermal energy refers to the energy possessed by an object or system due to the motion of its particles. This motion is considered kinetic energy. As thermal energy is directly related to the movement of particles, it can be concluded that thermal energy is kinetic in nature.
5.
Sound energy is...
Correct Answer
C. The energy caused by an object's vibrations.
Explanation
Sound energy is the energy caused by an object's vibrations. When an object vibrates, it creates sound waves that travel through a medium, such as air or water. These sound waves carry energy, which can be detected by our ears as sound. The energy of sound is directly related to the frequency and amplitude of the vibrations.
6.
What device converts chemical energy to mechanical energy?
Correct Answer
D. All of the above.
Explanation
All of the options listed (human, car, jet ski) can convert chemical energy to mechanical energy. In the case of humans, the chemical energy from food is converted into mechanical energy to perform physical tasks. Cars and jet skis convert the chemical energy from fuel (such as gasoline) into mechanical energy to power their engines and move. Therefore, all of these devices can convert chemical energy to mechanical energy.
7.
As height increases, so does...
Correct Answer
D. Potential energy.
Explanation
As height increases, potential energy also increases. This is because potential energy is the energy possessed by an object due to its position or height above the ground. The higher an object is, the greater its potential energy, as it has the potential to fall and convert that potential energy into other forms such as kinetic or mechanical energy. Therefore, as height increases, potential energy increases.
8.
The law of _________________ of energy states that energy cannot be created or destroyed.
Correct Answer
C. Conservation
Explanation
The law of conservation of energy states that energy cannot be created or destroyed. This means that the total amount of energy in a closed system remains constant over time. Energy can only be transformed from one form to another, such as from potential energy to kinetic energy. This principle is fundamental in understanding the behavior and interactions of energy in various systems and processes.
9.
According to the law of conservation of energy, in theory, a bouncy ball should never stop bouncing. However, we know that it eventually stops. Where does the energy go.
Correct Answer
C. Both A and B
Explanation
According to the law of conservation of energy, energy cannot be created or destroyed, only transferred or converted from one form to another. In the case of a bouncy ball, when it bounces, some of the energy is converted into sound energy, causing the ball to make a sound as it hits the ground and escapes into the surroundings. Additionally, some of the energy is converted into thermal energy due to the friction between the ball and the surface it bounces on. This thermal energy is also released into the surroundings. Therefore, both options A and B are correct explanations for where the energy goes when a bouncy ball eventually stops bouncing.
10.
Energy is...
Correct Answer
B. The ability to do work.
Explanation
The correct answer is "the ability to do work." This answer is correct because energy is defined as the capacity or ability to do work. Work is the transfer of energy from one object to another, and energy is required to perform any kind of work. Therefore, the ability to do work is a fundamental characteristic of energy.
11.
What is the most effective way of saving energy at home?
Correct Answer
A. Lowering your room temperature
Explanation
Lowering your room temperature is the most effective way of saving energy at home because heating accounts for a significant portion of energy consumption. By reducing the temperature, less energy is required to maintain a comfortable environment. This can be achieved by using a programmable thermostat or manually adjusting the temperature. Additionally, lowering the room temperature can also have health benefits such as better sleep and improved respiratory function.
12.
The most energy-efficient way of using your sauna.
Correct Answer
A. Heating it to 70-80C and turning it off as soon as you're done
Explanation
Heating the sauna to 70-80C and turning it off as soon as you're done is the most energy-efficient way of using the sauna. This temperature range is considered optimal for a sauna session, providing the desired heat and therapeutic benefits. By turning off the sauna immediately after use, unnecessary energy consumption is avoided. This approach ensures that energy is not wasted by keeping the sauna at a high temperature when it is not in use, resulting in energy efficiency and cost savings.
13.
We should turn on the dishwasher...
Correct Answer
C. When it is full of dishes
Explanation
The correct answer is "when it is full of dishes". This is because running the dishwasher when it is full of dishes is more efficient and saves water and energy compared to running it with only a few dishes. Additionally, waiting until the dishwasher is full reduces the frequency of running it, leading to less wear and tear on the appliance.
14.
When you leave a room, what should you do?
Correct Answer
A. Turn off the electrical appliances inside
Explanation
When leaving a room, it is important to turn off the electrical appliances inside to save energy and prevent any potential hazards. Leaving appliances on when they are not in use can lead to unnecessary electricity consumption and increase the risk of fire or accidents. Therefore, it is recommended to switch off all electrical appliances before leaving a room as a responsible and safe practice.
15.
It is very cool outside and you feel very hot inside, what should you do?
Correct Answer
B. Open the windows
Explanation
Opening the windows is the best solution in this situation because it allows fresh air to circulate and helps in cooling down the indoor temperature. Turning on the air conditioner may not be necessary if it is already cool outside, and using both the air conditioner and opening the windows would be inefficient and counterproductive.
16.
According to the ____________________________,energy is never created or destroyed.
Correct Answer
D. Law of conservation of energy
Explanation
The law of conservation of energy states that energy cannot be created or destroyed, but it can only be transformed or transferred from one form to another. This principle is based on the observation that the total amount of energy in a closed system remains constant over time. It is a fundamental concept in physics and is used to explain various phenomena, such as the conversion of potential energy to kinetic energy or the conservation of mechanical energy in a system.
17.
______________________ moves from the hot chocolate to the cooler surrounding.
Correct Answer
E. Thermal energy
Explanation
Thermal energy moves from the hot chocolate to the cooler surrounding because heat naturally flows from a higher temperature to a lower temperature. Thermal energy refers to the energy associated with the motion of particles within a substance. In this case, the hot chocolate has a higher temperature, so its thermal energy will transfer to the cooler surrounding until both reach equilibrium.
18.
What kind of device tranforms kinetic energy into electrical energy?
Correct Answer
A. Generater
Explanation
A generator is a device that transforms kinetic energy into electrical energy. It does this by using a rotating shaft, typically driven by an engine or turbine, to convert mechanical energy into electrical energy through the process of electromagnetic induction. This process involves the movement of a magnetic field through a coil of wire, creating an electric current. Therefore, a generator is the correct answer as it is specifically designed to convert kinetic energy into electrical energy.
19.
When something is high up, it has less potential energy.
Correct Answer
False
Explanation
The statement is false because when something is high up, it actually has more potential energy. Potential energy is the energy possessed by an object due to its position or height. The higher an object is, the greater its potential energy because it has the ability to do more work or exert more force when it falls or moves downward. Therefore, the statement contradicts the concept of potential energy and is incorrect.
20.
What kind of energy does a lightning strike have?
Correct Answer
Electrical energy
Explanation
A lightning strike has electrical energy because it is a massive discharge of electricity that occurs during a thunderstorm. Lightning is formed when there is a buildup of electrical charges in the atmosphere, and when the electrical potential difference becomes too great, it is released in the form of a lightning bolt. This discharge of electricity is extremely powerful and can generate temperatures hotter than the surface of the sun. Therefore, the correct answer is electrical energy.
21.
Energy transformations occur ______________ around you.
Correct Answer
E. Constantly
Explanation
Energy transformations occur constantly around you. This means that energy is constantly being converted from one form to another, such as from potential energy to kinetic energy or from electrical energy to light energy. These transformations happen all the time in various natural and man-made processes, ensuring that energy is continuously being transferred and utilized in different ways.
22.
When you listen to the radio, there are five energy steps. They are the electrical energy of the radio signal, kinetic energy from the speaker, sound energy of the air, kinetic energy of the eardrum and fluid, _______ energy of the brain and nerve cells.
Correct Answer
electrical energy
Explanation
The correct answer is electrical energy. When listening to the radio, the electrical energy of the radio signal is converted into kinetic energy by the speaker, producing sound energy in the air. This sound energy is then converted into kinetic energy in the eardrum and fluid, which stimulates the nerve cells in the brain, ultimately resulting in the perception of sound.
23.
Every day you use electrical energy.
Correct Answer
True
Explanation
Electrical energy is commonly used in our daily lives for various purposes such as lighting, heating, cooling, and powering electronic devices. From turning on a light bulb to charging our smartphones, we rely on electrical energy to perform numerous tasks. Therefore, it is true to say that we use electrical energy every day.
24.
______________ energy changes into thermal energy when a wire that is carrying an electric currentbgets hot.
Correct Answer
E. Electrical
Explanation
When a wire that is carrying an electric current gets hot, the electrical energy is converted into thermal energy. This happens due to the resistance in the wire, which causes the wire to heat up. As the electric current passes through the wire, the electrons collide with the atoms in the wire, generating heat energy. Therefore, the correct answer is electrical energy.
25.
A coal-burning power plant transforms the __________ energy in coal into electrical energy.
Correct Answer
chemical
Explanation
A coal-burning power plant transforms the chemical energy in coal into electrical energy. When coal is burned, the chemical bonds within the coal molecules break, releasing energy in the form of heat. This heat is then used to produce steam, which drives a turbine connected to a generator. The generator converts the mechanical energy from the turbine into electrical energy, which can be transmitted and used to power homes, businesses, and industries.