1.
The law of conservation of energy states...
Correct Answer
C. Energy cannot be created or destroyed, only transformed.
Explanation
The correct answer is "energy cannot be created or destroyed, only transformed." This statement is a fundamental principle in physics known as the law of conservation of energy. It states that the total amount of energy in a closed system remains constant over time. Energy can change from one form to another, such as potential energy to kinetic energy, but the total amount of energy remains constant. This principle is widely applicable and helps us understand various phenomena in the universe.
2.
Describe your energy at the top of a roller coaster hill, just before you start moving into the big drop. You are currently perfectly still (aside from the screaming).
Correct Answer
B. You have potential energy.
Explanation
Kinetic energy comes from motion.
3.
Suppose, you played with a generator (this was the gun-looking object with the crank on one end) yesterday. Why were you able to light up the lightbulb when you turned the crank?
Correct Answer
B. The energy you used to turn the crank was converted into electricity.
Explanation
When you turned the crank of the generator, the energy you exerted was converted into electricity. This conversion is made possible by the internal mechanisms of the generator, which typically involve a magnet and coils of wire. As you rotate the crank, the magnet spins inside the generator, inducing a current in the wire coils through electromagnetic induction. This current is then used to power the lightbulb, allowing it to light up. Therefore, the correct answer is that the energy from your physical effort was transformed into electrical energy.
4.
I stretch a rubberband and fling it at across the room. When does the rubber band have energy?
Correct Answer
C. Both when its stretched tight and when its flying across the room.
Explanation
When you stretch a rubberband, you are using your own energy to give the rubberband potential energy. When you release the band, its energy gets transformed into moving energy (kinetic energy).
5.
Where does electricity in your house come from (the type that comes on when you flip a switch)?
Correct Answer
C. Humans heat up water and create steam in order to spin magnets near wires.
Explanation
The correct answer is that humans heat up water and create steam in order to spin magnets near wires. This is a description of how electricity is generated in a power plant. The heat from burning coal or oil is used to heat up water and create steam, which in turn spins turbines that are connected to magnets. The spinning magnets generate electricity that is then transmitted through wires to our homes.
6.
The heat added to or removed from the system is represented by using which alphabet?
Correct Answer
C. Q
Explanation
The alphabet used to represent the heat added to or removed from the system is Q. In thermodynamics, Q represents the heat transfer, which can be positive when heat is added to the system or negative when heat is removed from the system. The other options, U, W, and H, are commonly used to represent internal energy, work, and enthalpy respectively, but not specifically heat transfer.
7.
Conservation of energy applies only to isolated systems.
Correct Answer
A. True
Explanation
The statement is true because the conservation of energy principle states that energy cannot be created or destroyed, only transferred or transformed. This principle applies specifically to isolated systems, which are systems that do not interact with their surroundings and do not exchange energy or matter with the external environment. In isolated systems, the total amount of energy remains constant over time. However, in non-isolated systems, energy can be lost or gained through interactions with the surroundings, violating the principle of conservation of energy. Therefore, conservation of energy only applies to isolated systems.
8.
Solar panels can generate solar energy.
Correct Answer
A. True
Explanation
Solar panels are specifically designed to convert sunlight into electrical energy through the photovoltaic effect. They do generate solar energy by capturing sunlight and transforming it into usable electricity, which is a form of solar energy. Therefore, the correct answer is true.
9.
The unit of energy is
Correct Answer
B. Joule
Explanation
The unit of energy is Joule. Joule is the standard unit of energy in the International System of Units (SI). It is defined as the amount of work done when a force of one newton is applied over a distance of one meter. Energy is a fundamental physical quantity that is used to measure the capacity of a system to do work or produce heat.
10.
Who proposed first, "Energy can neither be created nor be destroyed."?
Correct Answer
A. Émilie du Châtelet
Explanation
Émilie du Châtelet proposed the idea that energy cannot be created or destroyed. This concept is known as the law of conservation of energy and is a fundamental principle in physics. It states that the total amount of energy in a closed system remains constant over time, although it can change forms. This idea was later developed and expanded upon by other scientists, including Julius Robert von Mayer, James Prescott Joule, and Hermann Ludwig Ferdinand. However, Émilie du Châtelet is credited with being one of the first to propose this concept.