PTEC 131 - Exam 1 - Fall 14

Temperature is the correct answer because it refers to a specific degree of hotness or coldness. It is measured and indicated on a reference scale, such as Celsius or Fahrenheit. Temperature is a fundamental concept in thermodynamics and is used to describe the level of heat energy in a system. It is an important parameter in various scientific and everyday applications, including weather forecasting, cooking, and regulating the comfort level in buildings.

A local instrument is a term used to refer to an instrument that is used in a specific location or field. It is typically used to measure or monitor a specific parameter or variable within that location. Therefore, it can be said that a local instrument is also called a field instrument, as both terms refer to the same concept.

The correct answer is "Remote" because an instrument that is located away from the process is considered remote. This means that the instrument is not physically close to the process it is monitoring or controlling. Instead, it is positioned at a distance, allowing for remote monitoring and control of the process.

The correct answer is "Local" because an instrument located near the process refers to a device that is situated in close proximity to the process being monitored or controlled. This implies that the instrument is physically present in the same area or vicinity as the process, allowing for direct observation or manipulation.

Pressure is defined as the force applied to a unit area. It is a measure of how much force is distributed over a given area. When a force is applied to a surface, the pressure is calculated by dividing the force by the area. This concept is important in various fields such as physics, engineering, and fluid dynamics, where pressure plays a crucial role in understanding and predicting the behavior of fluids and materials.

According to the ideal gas law, when temperature increases, the average kinetic energy of gas molecules increases. This causes the gas molecules to move faster and collide with the walls of the container more frequently and with greater force, resulting in an increase in pressure. Therefore, it is true that when temperature increases, pressure increases.

Differential pressure refers to the difference in pressure between two separate points. It is a measurement that helps determine the pressure drop across a system or device. By comparing the pressure at two different points, it is possible to calculate the flow rate or detect any blockages or leaks in the system. Therefore, the correct answer is "Differential Pressure" as it accurately describes the concept of the difference between measurements taken from two separate points.

An instrument powered by electricity is referred to as electronic. Electronic instruments use electrical energy to operate and are commonly found in various fields such as telecommunications, computing, and measurement devices. They rely on electronic components and circuits to process and transmit information, making them a suitable choice for precise and efficient control and measurement systems.

This statement is known as Gay-Lussac's Law, which states that when the pressure of a gas increases, its temperature also increases, assuming the volume and amount of gas remain constant. This is because the increase in pressure causes the gas molecules to collide more frequently and with greater force, resulting in an increase in kinetic energy and therefore temperature.

A pneumatic instrument is powered by air or other gases. This means that it uses compressed air or gas to operate and perform its functions. Pneumatic instruments are commonly used in various industries and applications where precise control and automation are required. They are known for their reliability, simplicity, and cost-effectiveness. Pneumatic instruments are often used in control systems to measure and control pressure, flow, temperature, and other variables.

Analog signals can be transmitted both pneumatically and electronically. Pneumatic transmission involves the use of air pressure to carry the analog signal, while electronic transmission involves the use of electrical signals. Both methods are capable of transmitting analog signals, making the statement true.

The term "analytical" refers to the use of a logical technique to perform an analysis. In this context, it suggests that the use of a logical technique is the correct answer for the given question. The other options, specific gravity and differential pressure, do not directly relate to the use of a logical technique for analysis. Therefore, "analytical" is the most appropriate answer.

In order to ensure accurate measurement, all variables must be accounted for. This means that any factors that can potentially affect the measurement, such as pressure, temperature, and flow, need to be taken into consideration. Ignoring any of these variables could lead to inaccurate results.

Flow is the quantity of fluid moving within a given period of time. It represents the rate at which the fluid is moving or being transferred. This can be measured in terms of volume or mass per unit of time. Flow is an important concept in fluid dynamics and is used to describe the movement of fluids in various systems and processes.

The correct answer is the difference between measurements taken from two separate points. This means that the term "differential" refers to the comparison or contrast between two measurements or values that are obtained from different locations or points. It does not refer to a force applied to a unit of area, the quantity of fluid that moves through a pipe, or the position of height or depth along a vertical axis.

Level is the correct answer because it refers to the height of the surface of a material compared to a zero reference point. It indicates the position of the surface relative to a specific point or plane, serving as a measurement of height or elevation.

A control loop refers to a group of instruments that work together to control a single process variable. These instruments typically include sensors, controllers, and actuators. The sensors measure the process variable, the controller compares the measured value to the desired value, and the actuators adjust the process to bring it back to the desired value. This closed-loop system allows for continuous monitoring and adjustment of the process variable, ensuring it stays within the desired range.

When density increases, temperature will decrease because an increase in density means that there are more particles packed into a given volume. This increased packing causes the particles to collide more frequently, leading to a decrease in their average kinetic energy, which is manifested as a decrease in temperature.

When flow increases, pressure will decrease because as more fluid flows through a pipe or system, there is less resistance to the flow, resulting in a decrease in pressure. This can be observed in various fluid dynamics applications, such as in a water pipe or in the cardiovascular system, where increased blood flow leads to a decrease in blood pressure. Therefore, it is true that when flow increases, pressure will decrease.

According to the Bernoulli Principle, as the speed of a moving fluid increases, the pressure within the fluid decreases. This is because when the fluid moves faster, the molecules have less time to collide with each other or with the walls of the container, resulting in a decrease in pressure.

Process variables are measured properties of a process. These variables include factors such as rate, pressure, flow, and mass, which are used to monitor and control the process. By measuring these variables, operators can assess the performance of the process and make necessary adjustments to ensure its efficiency and effectiveness. Therefore, process variables play a crucial role in understanding and managing industrial processes.

The statement is incorrect. According to the ideal gas law, when volume increases, temperature will also increase, assuming the pressure and amount of gas remain constant. This is known as Charles's Law. Therefore, the correct answer is False.

When head (bottom) pressure increases, the height of the liquid does not decrease. In fact, when the pressure at the bottom of a liquid column increases, the height of the liquid column also increases. This is due to the relationship between pressure and height in a fluid, known as Pascal's law. According to Pascal's law, an increase in pressure at any point in a confined fluid is transmitted equally to all parts of the fluid, resulting in an increase in height. Therefore, the correct answer is false.

A tank is a rigid structure, meaning it does not change shape easily. Therefore, its volume remains constant.

Digital is the correct answer because it refers to a transmission method that uses discrete electrical signals instead of continuous signals. In digital transmission, information is represented by a series of binary digits (0s and 1s), allowing for more precise and reliable communication compared to analog transmission. This method is commonly used in various technologies, including computers, telecommunications, and audio/video systems.

When pressure is applied to the surface of a liquid, it increases the force exerted on the liquid molecules, making it more difficult for them to escape into the gas phase. This results in an increase in the boiling point of the liquid. Therefore, pressure directly affects the boiling point of a liquid.

An indicating instrument is used to display the current conditions of the process variable or the output signal of other instruments. It provides a visual representation of the measurement or signal, allowing operators to quickly and easily monitor the status of the process. Unlike transmitting instruments, which send the measurement or signal to another location, or recording instruments, which record data over time, indicating instruments focus on immediate visualization. Controlling instruments, on the other hand, are used to adjust and maintain the desired value of the process variable.

The given statement suggests that the head pressure will increase as the liquid height increases. However, it also states that this is true only if the density of the liquid remains constant. This means that the liquid's density does not change with the increase in liquid height. Therefore, the correct answer is "Remains constant" as the head pressure will only increase if the density remains constant.

Charles' Law states that the volume of a gas is directly proportional to its temperature, assuming that pressure and amount of gas remain constant. The formula P1 / T1 = P2 / T2 represents Charles' Law because it shows the relationship between the initial pressure and temperature (P1 and T1) and the final pressure and temperature (P2 and T2) of a gas sample. As the temperature increases, the volume of the gas also increases, and vice versa, as long as the pressure and amount of gas remain constant.