1.
Electricity can only flow if a circuit is ___.
Correct Answer
C. Closed
Explanation
Electricity can only flow if a circuit is closed. In a closed circuit, there is a complete path for the electric current to flow, allowing the flow of electrons from the power source to the load and back. This means that all components of the circuit, such as wires, switches, and devices, are connected in a continuous loop, enabling the uninterrupted flow of electricity. In contrast, an open circuit has a break or gap in the path, preventing the flow of electricity. Therefore, a closed circuit is necessary for the proper functioning of electrical systems.
2.
Look at the picture. When electricity is turned on, which force is produced?
Correct Answer
A. Magnetic force
Explanation
When electricity is turned on, a magnetic force is produced. This is due to the interaction between the electric current and the magnetic field. As the electric current flows through a wire, it creates a magnetic field around it. This magnetic field can then exert a force on nearby magnetic materials or other electric currents, resulting in a magnetic force. This phenomenon is the basis for many electrical devices such as motors and generators.
3.
In a radio, electrical energy is changed into ___.
Correct Answer
B. Sound
Explanation
In a radio, electrical energy is changed into sound. This is because the electrical signals received by the radio are converted into sound waves by the speaker, allowing us to hear the audio being transmitted.
4.
A D-cell battery is a source of __________________
Correct Answer
A. Electricity
Explanation
A D-cell battery is a source of electricity. It is designed to convert chemical energy into electrical energy through a chemical reaction. When connected in a circuit, the battery's internal chemical reactions produce a flow of electrons, creating an electric current that can power various devices or systems.
5.
What is a pathway for the flow of electricity?
Correct Answer
A. Circuit
Explanation
A pathway for the flow of electricity is called a circuit. A circuit is a closed loop that allows electric current to flow from a power source, through various components such as wires, resistors, and switches, and back to the source. It provides a complete path for the flow of electrons, enabling the transfer of electrical energy to power devices or perform tasks.
6.
What provides the energy to light a light bulb?
Correct Answer
D. Electricity source
Explanation
An electricity source provides the energy to light a light bulb. When the electricity source is connected to the circuit board, it generates an electric current that flows through the circuit and reaches the light bulb. The electric current then passes through the filament of the light bulb, which heats up and produces light energy. Therefore, the electricity source is responsible for providing the necessary energy to power the light bulb and create light.
7.
In a simple series circuit, why does the bulb light when you close the switch?
Correct Answer
B. Closing the switch completes the circuit
Explanation
When you close the switch in a simple series circuit, it completes the circuit by allowing the flow of electricity. This means that the current can now flow from the power source through the switch, through the bulb, and back to the power source, creating a complete loop. As a result, the bulb lights up because it is now receiving the necessary electrical energy to produce light.
8.
If there is a 1.5V battery and a bulb on a simple series circuit and the battery is changed to a 3V, what happens to the bulb?
Correct Answer
B. It gets brighter
Explanation
When the battery is changed from 1.5V to 3V in a simple series circuit, the voltage across the bulb increases. Since the brightness of a bulb is directly proportional to the voltage across it, the bulb gets brighter.
9.
A lead-acid battery stores what kind of electricity?
Correct Answer
B. Direct current (DC)
Explanation
A lead-acid battery stores direct current (DC) electricity. Unlike alternating current (AC), which periodically changes direction, DC flows in one direction continuously. This type of electricity is commonly used in batteries as it allows for a steady and consistent flow of energy. Lead-acid batteries are commonly used in vehicles and backup power systems, where they convert chemical energy into electrical energy and store it as DC power.