1.
Christmas tree lights are often connected in series. This is not a good idea because
Correct Answer
C. If one light breaks, they all go out.
Explanation
When Christmas tree lights are connected in series, it means that the current flows through each light in sequence. If one light breaks or stops working, it creates an open circuit, causing the current to stop flowing and all the other lights to go out as well. This is why connecting Christmas tree lights in series is not a good idea, as it can easily lead to a situation where one faulty light affects the entire string of lights.
2.
Electrical current is the flow of electrical charges (electrons) through a circuit.
Correct Answer
A. True
Explanation
Electrical current refers to the movement of electric charges, specifically electrons, through a circuit. When a voltage is applied to a circuit, the electrons are pushed by the electric field and start to flow, creating a current. This flow of electrons is what allows electrical devices to operate and is the basis of many electrical systems. Therefore, the statement that electrical current is the flow of electrical charges (electrons) around a circuit is true.
3.
The more bulbs you add to a circuit in series, the more difficult it will be for the current to flow?
Correct Answer
A. True
Explanation
When you add more bulbs to a circuit, the total resistance of the circuit increases. According to Ohm's Law (V = IR), if the resistance increases, the current flowing through the circuit decreases. Therefore, it becomes more difficult for the current to flow as more bulbs are added to the circuit.
4.
In the picture, what does the short line represent?
Correct Answer
D. Negative Terminal
Explanation
In a diagram representing a cell (battery), the short line usually denotes the negative terminal or the cathode. This terminal is where electrons flow out of the cell during discharge, forming the negative pole of the battery.
5.
What is an energy storage device composed of electrochemical cells?
Correct Answer
C. A battery
Explanation
A battery is an energy storage device composed of electrochemical cells. Electrochemical cells convert chemical energy into electrical energy through a chemical reaction. This allows the battery to store and release energy as needed. A fuse is a safety device that protects electrical circuits from overloads, a flashlight is a portable light source, and a circuit is a path through which electric current can flow. None of these options accurately describe an energy storage device composed of electrochemical cells like a battery does.
6.
All lamps have some resistance. Putting a lamp with large resistance into a circuit will
Correct Answer
C. Make the current smaller.
Explanation
When a lamp with a large resistance is added to a circuit, it will restrict the flow of current in the circuit. This is because resistance opposes the flow of current. As a result, the current passing through the circuit will decrease. The voltage across the lamp may not change significantly, as it depends on the overall resistance and the potential difference applied to the circuit. However, the current will be reduced due to the presence of the lamp with large resistance.
7.
Which group of items are conductors?
Correct Answer
B. B
Explanation
Group B is the correct answer because conductors are materials that allow the flow of electric current. The other groups, A, C, and D, may consist of non-conductive materials or items that do not facilitate the movement of electric charges.
8.
You have identical lamps and cells. Which combination gives the brightest circuit?
Correct Answer
A. Two cells connected to one lamp
Explanation
Connecting two cells to one lamp will provide the brightest circuit. This is because the voltage supplied by the two cells will be additive, resulting in a higher voltage across the lamp. This increased voltage will cause the lamp to emit more light, making the circuit brighter compared to the other combinations.
9.
Two lamps are connected side-by-side so that the current is shared between them. We call this connected.
Correct Answer
B. In a parallel
Explanation
When two lamps are connected side-by-side in a parallel circuit, it means that they are connected to the same voltage source but have separate branches for the current to flow through. In this configuration, the current is shared between the lamps, meaning that each lamp receives the same voltage and can operate independently. This is different from a series circuit where the lamps would be connected in a single path, causing the same current to flow through both lamps.
10.
Lamps in your house are often connected in parallel. This is a good idea because
Correct Answer
C. You can switch them off separately.
Explanation
The correct answer is "You can switch them off separately." When lamps are connected in parallel, each lamp has its own separate circuit, allowing you to control each one individually. This means that you can turn off one lamp without affecting the others, providing flexibility and convenience in lighting control.
11.
A series circuit has one path from the source and back to the source again.
Correct Answer
A. True
Explanation
A series circuit is a type of electrical circuit where the components are connected in a single loop, creating only one path for the current to flow from the source and back to the source again. In this configuration, the components are connected end-to-end, with the same current flowing through each component. Therefore, the statement is true.
12.
What is the name of this piece of equipment?
Correct Answer
B. An open switch
Explanation
The correct answer is "An open switch." An open switch refers to a switch that is not connected, resulting in a break in the circuit and the flow of current being interrupted. In this case, the image provided does not show any connection between the two ends of the switch, indicating that it is open and not allowing the flow of electricity.
13.
If you unscrew one of the light bulbs in a parallel circuit, the rest will stop lighting.
Correct Answer
B. False
Explanation
In a parallel circuit, each light bulb has its own separate path for current to flow. If one light bulb is unscrewed or removed, the other light bulbs will continue to receive current and remain lit. Therefore, the statement that the rest of the light bulbs will stop lighting if one is unscrewed is false.
14.
Glass is a conductor of electricity.
Correct Answer
B. False
Explanation
Glass is not a conductor of electricity. It is actually an insulator. Insulators are materials that do not allow the flow of electric current. Glass is made up of non-metallic elements, which have tightly bound electrons that do not move freely. This lack of free-moving electrons prevents the flow of electricity through glass. Therefore, the statement that glass is a conductor of electricity is false.
15.
Electricity is a force.
Correct Answer
B. False
Explanation
Electricity is not a force, but rather a form of energy resulting from the flow of electric charge. It is a phenomenon that involves the movement of electrons through a conductor, which can generate various effects such as heat, light, or the ability to perform work. While electricity can create forces, such as the attractive or repulsive forces observed in electromagnetism, it is not a force in itself.
16.
What is the main energy transfer in a lamp?
Correct Answer
D. Electrical to light
Explanation
The main energy transfer in a lamp is from electrical energy to light energy. When the lamp is connected to a power source, the electrical energy flows through the circuit and is converted into light energy by the lamp's filament or LED. This light energy is then emitted from the lamp, allowing us to see and illuminate our surroundings.
17.
Electric current gets used up in a circuit.
Correct Answer
B. False
Explanation
False. Electric current itself does not get used up in a circuit. It is the flow of electric charge (usually carried by electrons) through a conductor. In a closed circuit, electric current flows continuously from the source (e.g., battery) through the components and back to the source. However, the energy carried by the electric current can be transformed into other forms, such as heat, light, or mechanical energy, as it passes through resistive elements in the circuit.
18.
This is the circuit symbol for which piece of electrical equipment?
Correct Answer
A. A battery
Explanation
The circuit symbol shown in the question represents a battery. A battery is a device that stores and provides electrical energy. It consists of one or more electrochemical cells, which convert chemical energy into electrical energy. The symbol typically consists of a long line representing the positive terminal, a shorter line representing the negative terminal, and sometimes additional lines or symbols to indicate the type and voltage of the battery.
19.
Electricity flows through a wire. We call this a current. Current is measured in what units?
Correct Answer
B. Amps
Explanation
Electricity flowing through a wire is measured in units of amps, short for amperes. Amps represent the rate of flow of electric charge, indicating the amount of current passing through a point in a circuit per unit of time. It is named after the French physicist André-Marie Ampère, who made significant contributions to the study of electromagnetism.