1.
What is the unit for voltage?
Correct Answer
A. Volts
Explanation
The unit for voltage is volts. Voltage is a measure of the electric potential difference between two points in a circuit. It represents the amount of energy that each unit of charge possesses. The volt is named after the Italian physicist Alessandro Volta, who invented the first battery. Volts are used to measure the potential difference in electrical systems and are a fundamental unit in electrical engineering and physics.
2.
What is the unit for current?
Correct Answer
B. Amperes
Explanation
The unit for current is amperes. Current is a measure of the flow of electric charge in a circuit. It represents the rate at which charges move through a conductor. Amperes, symbolized by A, is the standard unit for measuring electric current. Volts, ohms, and joules are not units of current. Volts measure electric potential difference, ohms measure resistance, and joules measure energy.
3.
What is the unit for resistance?
Correct Answer
C. Ohms
Explanation
The unit for resistance is ohms. Resistance is a measure of how much a material or device impedes the flow of electric current. It is represented by the symbol Î© and is named after the German physicist Georg Simon Ohm. Ohms is the standard unit used to quantify resistance in electrical circuits. Volts, amperes, and joules are all units used to measure other electrical quantities such as voltage, current, and energy respectively.
4.
Which of these is the equation for Ohm's Law?
Correct Answer
B. V = IR
Explanation
Ohm's Law states that the voltage across a conductor is directly proportional to the current flowing through it, and inversely proportional to the resistance of the conductor. The equation V = IR represents this relationship, where V is the voltage, I is the current, and R is the resistance.
5.
A certain steam iron carries a current of 6.4 A when connected to a 120 V source. What is the resistance of the steam iron?
Correct Answer
D. 18.75 Î©
Explanation
When a current of 6.4 A flows through a steam iron connected to a 120 V source, the resistance of the steam iron can be calculated using Ohm's Law, which states that resistance (R) is equal to voltage (V) divided by current (I). Therefore, the resistance of the steam iron is calculated as 120 V / 6.4 A = 18.75 Î©.
6.
The resistance of a hotplate is 48 Î© . How much current does the plate carry when connected to a 120-V source?
Correct Answer
B. 2.5 A
Explanation
The current flowing through a circuit can be calculated using Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is given as 120 V and the resistance is given as 48 Î©. By substituting these values into the formula, we can calculate the current as 2.5 A.
7.
A typical size-D battery has about how many volts?
Correct Answer
C. 1.5 V
Explanation
A typical size-D battery has a voltage of 1.5 V. This is a common voltage rating for many household batteries, including AA, AAA, C, and D batteries. The voltage rating indicates the electrical potential difference between the positive and negative terminals of the battery. A higher voltage rating means the battery can deliver more electrical energy, while a lower voltage rating means it has a lower capacity. In the case of a size-D battery, it is designed to provide a steady 1.5 V output for devices that require a higher power supply.
8.
Voltage is a measurement of what?
Correct Answer
C. Potential energy stored in a battery
Explanation
Voltage is a measurement of potential energy stored in a battery. Voltage represents the amount of electric potential energy per unit charge that is available in a circuit. In the case of a battery, it stores chemical potential energy, which is converted into electrical potential energy when a circuit is connected. This potential energy drives the flow of electrons, creating an electric current. Therefore, voltage is a measurement of the potential energy that can be converted into electrical energy in a circuit.
9.
Electrical Power is measured in :
Correct Answer
A. Watts
Explanation
Electrical power is measured in watts. Watts is the unit of power and it represents the rate at which energy is consumed or produced. It is calculated by multiplying the voltage (in volts) by the current (in amperes). Watts is commonly used to measure the power output or consumption of electrical devices and systems.