1.
A dual-element fuse is used to:
Correct Answer
B. Operate at a higher current.
Explanation
A dual-element fuse is used to operate at a higher current. This type of fuse contains two elements, one for normal current and another for higher current. The purpose of the dual-element fuse is to provide protection against temporary overloads that may occur in electrical circuits. When a temporary overload occurs, the dual-element fuse can handle the higher current without blowing, ensuring the circuit remains operational. This helps prevent damage to the circuit and its components.
2.
If the current is 12 amperes and the voltage is 15 volts, what is the resistance?
Correct Answer
D. 1.25 ohms
Explanation
Multiply the current by the electrical resistance to calculate the voltage. For example, if the current is 2.5 amperes and the resistance is 15 ohms, then the voltage = 2.5 amperes x 15 ohms = 37.5 volts.
3.
When an alternating voltage is applied to a purely resistive circuit, the:
Correct Answer
D. Current is in phase with the voltage.
Explanation
When an alternating voltage is applied to a purely resistive circuit, the current is in phase with the voltage. This means that both the current and voltage reach their maximum and minimum values at the same time. In a purely resistive circuit, there is no reactance or capacitance to cause a phase shift between the current and voltage. Therefore, they are in phase with each other.
4.
If a fuse blows when the start button is pressed, what should you check for?
Correct Answer
A. Shorted motor circuit
Explanation
If a fuse blows when the start button is pressed, it indicates a shorted motor circuit. This means that there is a fault in the motor circuit causing excessive current flow, which leads to the fuse blowing to protect the circuit from further damage. To troubleshoot this issue, one should inspect the motor circuit for any short circuits or faulty connections that may be causing the excessive current flow.
5.
The symbol for energy is:
Correct Answer
D. J
Explanation
The symbol for energy is represented by the letter "J". This is because "J" is the abbreviation for joule, which is the standard unit of energy in the International System of Units (SI). The joule is named after James Prescott Joule, a British physicist who made significant contributions to the study of energy. Therefore, "J" is the correct symbol to represent energy.
6.
The base unit of energy is the:
Correct Answer
C. Joule
Explanation
The correct answer is joule because joule is the base 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. The other options, ion, proton, and pound, are not units of energy but rather refer to different particles or units of mass.
7.
The abbreviation for the base unit of energy is:
Correct Answer
D. J
Explanation
The correct answer is "j" which stands for joule. Joule is the base unit of energy in the International System of Units (SI). It is used to measure various forms of energy such as mechanical, thermal, and electrical energy. The joule is defined as the amount of energy transferred when a force of one newton is applied over a distance of one meter.
8.
A positive ion is an atom which has:
Correct Answer
B. Given up one or more electrons
Explanation
A positive ion is an atom that has given up one or more electrons. When an atom loses one or more electrons, it becomes positively charged because there are more protons than electrons. This creates an imbalance of positive charge, resulting in a positive ion.
9.
A joule per second defines a:
Correct Answer
C. Watt
Explanation
A joule per second is the unit of power, which is the rate at which work is done or energy is transferred. Therefore, a joule per second defines a watt, as watt is the unit of power in the International System of Units (SI).
10.
A coulomb per second defines a:
Correct Answer
B. Ampere
Explanation
A coulomb per second defines an ampere because the ampere is the unit of electric current, and a coulomb per second represents the rate of flow of electric charge. The ampere is defined as one coulomb of charge passing through a given point in one second. Therefore, a coulomb per second is equivalent to an ampere.
11.
Electric energy is converted into heat energy by:
Correct Answer
D. Resistance
Explanation
Resistance is the correct answer because it is a property of a material that opposes the flow of electric current. When an electric current passes through a resistor, the resistance causes the electrons to collide with atoms in the material, resulting in the conversion of electric energy into heat energy. This process is known as Joule heating. Therefore, resistance plays a crucial role in converting electric energy into heat energy.
12.
The charge has base units of:
Correct Answer
A. Coulombs
Explanation
The charge has base units of coulombs because coulomb is the SI unit of electric charge. It is defined as the amount of charge transported by a constant current of one ampere in one second. Therefore, coulombs is the correct unit to measure electric charge.
13.
Voltage has base units of:
Correct Answer
D. Volts
Explanation
Voltage is a measure of electric potential difference, which is the force that drives electric current. It is measured in volts, making it the correct answer. Ohms measure resistance, amperes measure current, and watts measure power, but none of these are the base units for voltage.
14.
Resistance has a base unit of:
Correct Answer
A. Ohms
Explanation
Resistance is a measure of how much a material or component opposes the flow of electric current. It is determined by the ratio of voltage to current, and its unit is ohms. Ohms is the correct base unit for resistance because it represents the amount of opposition to the flow of current in a circuit. Amperes represent the unit for current, watts represent the unit for power, and volts represent the unit for voltage.
15.
Current has a base unit of:
Correct Answer
B. Amperes
Explanation
The base unit of current is amperes. Current is the flow of electric charge in a circuit, and it is measured in amperes (A). Ohms is the base unit of resistance, watts is the base unit of power, and volts is the base unit of voltage. However, none of these units represent the base unit of current.
16.
The ability to do work is a definition of:
Correct Answer
B. Energy
Explanation
Energy is defined as the ability to do work. Work is the transfer of energy from one object to another, or the transformation of energy from one form to another. Therefore, energy is the correct answer as it encompasses the concept of being able to do work. Charge, on the other hand, refers to the property of matter that causes it to experience a force when placed in an electromagnetic field, and is not directly related to the ability to do work.