Comprehension And Aptitude Skills Lab Quiz

A flapper nozzle is used in a pneumatic controller. Pneumatic controllers use compressed air or gas to control and regulate various processes. The flapper nozzle is a component within the controller that helps to regulate the flow of air or gas. It is designed to allow for precise control and adjustment of the pressure or flow rate in pneumatic systems. Therefore, the correct answer is pneumatic.

The NOR gate is considered a universal gate because it can be used to implement any other logic gate. By connecting NOR gates in specific configurations, it is possible to create circuits that perform the functions of other gates such as AND, OR, and NOT. This versatility makes the NOR gate a fundamental building block in digital logic design.

A differential amplifier is a circuit whose output is proportional to the difference between the input signals. It amplifies the voltage difference between two input signals while rejecting any common-mode signals that are present. This type of amplifier is commonly used in applications where it is necessary to amplify the difference between two signals while ignoring any noise or interference that is present in both signals.

An XOR gate, also known as an exclusive OR gate, produces an output only when its two inputs are different. If the inputs are the same (both high or both low), the output of the XOR gate will be low. However, if the inputs are different (one high and one low), the output of the XOR gate will be high. Therefore, the correct answer is "different".

In a DMA write operation, the data is transferred from the I/O (input/output) device to the memory. This means that the data is being moved from the external device (such as a hard drive or network card) to the computer's main memory for processing or storage. DMA (Direct Memory Access) allows for efficient data transfer without involving the CPU, improving overall system performance.

The ratio between differential gain and common-mode gain is referred to as common-mode rejection. This term is used to describe the ability of a system to reject common-mode signals, which are unwanted signals that appear on both input terminals of a differential amplifier. A high common-mode rejection ratio indicates that the amplifier is effective in amplifying the desired differential signal while rejecting common-mode noise or interference.

The octal form of the decimal number 29 is 35. In octal representation, each digit represents a value from 0 to 7. To convert decimal to octal, we divide the decimal number by 8 and write down the remainder as the rightmost digit in the octal number. We continue this process by dividing the quotient by 8 until the quotient becomes 0. The octal form of 29 is obtained by arranging the remainders in reverse order, resulting in 35.

A rotameter is not a differential pressure flow meter because it operates on the principle of variable area flow measurement. It consists of a tapered tube with a float inside that rises or falls as the flow rate changes. The position of the float indicates the flow rate, and there is no differential pressure measurement involved. In contrast, flow nozzle, venturimeter, and orificemeter are all examples of differential pressure flow meters that measure the pressure difference across a constriction in the flow path to determine the flow rate.

Thermal wells are used in temperature measurement to guard against corrosive and oxidizing action on thermocouple materials. This is because thermocouples are often made of metals that can be easily corroded or oxidized when exposed to certain environments. By using a thermal well, the thermocouple is protected from direct contact with the corrosive or oxidizing substances, ensuring its longevity and accuracy in temperature measurement.

A negative gain margin expressed in decibels indicates that the system is unstable. In a stable system, the gain margin is typically positive, indicating that the system can tolerate a certain amount of gain before becoming unstable. However, a negative gain margin suggests that even a small increase in gain can cause the system to become unstable, making it an unstable system.

Ohm's law states that the current flowing through a conductor is directly proportional to the voltage applied across it, and inversely proportional to its resistance. However, this law is not applicable to semiconductors. Semiconductors are materials that have electrical conductivity between that of a conductor and an insulator. Their electrical behavior is more complex and cannot be accurately described by Ohm's law.

The Kelvin double bridge is best suited for the measurement of low resistance. This is because the Kelvin bridge is designed to eliminate the resistance of the connecting leads, which can be significant when measuring low resistance values. The bridge configuration allows for accurate measurements by balancing the unknown resistance with a known resistance, and the Kelvin method ensures that the resistance of the leads does not affect the measurement. Therefore, the Kelvin double bridge is an ideal choice for accurately measuring low resistance values.

An astable multivibrator is known as a free-running multivibrator because it continuously oscillates between two states without any external triggering. It does not require any external input to switch between its stable states. The circuit generates a continuous square wave output, where the duration of each state is determined by the values of the timing components used in the circuit. This makes it suitable for applications such as timing circuits, clock generators, and frequency dividers.

A TRIAC is a three-terminal semiconductor device that acts as a switch for alternating current (AC) circuits. It can be triggered by either a positive or a negative gate voltage. This means that the TRIAC can be turned on and off by applying either a positive or a negative voltage to its gate terminal, allowing it to control the flow of current in both directions. This flexibility in triggering makes the TRIAC suitable for various applications where bidirectional control of AC power is required.

When transistors are used in digital circuits, they usually operate in the saturation and cutoff regions. In the saturation region, the transistor is fully turned on and allows maximum current to flow through it. This represents a logical "1" in digital circuits. In the cutoff region, the transistor is fully turned off and no current flows through it. This represents a logical "0" in digital circuits. By operating in these two regions, transistors can effectively switch between on and off states, allowing them to perform the binary calculations required in digital circuits.

In a transistor, the collector current is controlled by the base current. The base current determines the amount of current flowing through the base-emitter junction, which in turn controls the flow of current between the collector and emitter. By varying the base current, the collector current can be regulated, allowing for amplification and switching functions in transistor circuits. The collector voltage and collector resistance do not directly control the collector current, although they may have an indirect effect on the transistor's operation.

A voltage follower is an amplifier circuit that has a closed-loop voltage gain of unity, meaning that the output voltage follows the input voltage exactly. This is achieved by using negative feedback, where a portion of the output voltage is fed back to the input to reduce any discrepancy between the input and output voltages. As a result, the closed-loop bandwidth of a voltage follower is zero, indicating that it cannot amplify high-frequency signals effectively. Additionally, a voltage follower typically has a small open-loop voltage gain and a large closed-loop output impedance.

A hall effect sensor is a device that detects and measures magnetic fields. It works based on the principle of the Hall effect, where a voltage is generated across a conductor when it is exposed to a magnetic field. This voltage can be used to determine the presence, strength, and polarity of the magnetic field. Therefore, a hall effect sensor is specifically designed to sense magnetic fields and is commonly used in various applications such as automotive systems, industrial machinery, and electronic devices.

The Maxwell bridge is a type of bridge circuit that is specifically designed for the measurement of inductance. It is used to accurately determine the value of an unknown inductance by comparing it with known values of resistances and capacitances. By achieving balance in the bridge circuit, the unknown inductance can be calculated. Therefore, the correct answer is inductance.

The ammeter has the lowest resistance among the given options. An ammeter is designed to measure electric current, and it needs to have a very low resistance in order to minimize the impact on the circuit being measured. By having low resistance, the ammeter ensures that it does not alter the current flow significantly, providing accurate readings. In contrast, a voltmeter measures voltage and typically has a much higher resistance, while a megger measures insulation resistance and a frequency meter measures frequency, neither of which require low resistance.

A psychrometer is a device used to measure the humidity of gases. It consists of two thermometers, one of which is a wet-bulb thermometer covered with a wet cloth. As the water on the wet-bulb evaporates, it cools the thermometer, and the difference in temperature between the wet-bulb and the dry-bulb thermometer is used to calculate the relative humidity of the air. Therefore, a psychrometer is specifically designed to determine the humidity of gases.

The working principle of a radiation pyrometer is based on the Stefan-Boltzmann law. This law states that the total radiation emitted by a black body is directly proportional to the fourth power of its absolute temperature. In the case of a radiation pyrometer, it measures the intensity of thermal radiation emitted by an object and uses this information to determine its temperature. By applying the Stefan-Boltzmann law, the pyrometer can calculate the temperature of the object based on the amount of radiation it emits.

The response of a system to a sinusoidal input is called frequency response. This is because the behavior of the system varies with different frequencies of the input signal. The frequency response of a system can be represented by a graph showing how the system's output amplitude and phase change with different frequencies of the input signal. It is an important concept in the field of signal processing and is used to analyze and design systems such as filters and amplifiers.

The given question is asking for the dead time in a unity gain, first order plus time delay process. The time constant of this process is given as 5 min. The phase lag at a frequency of 0.2 rad/min is given as 60°. To find the dead time, we need to convert the phase lag from degrees to radians. Since 180° is equal to π radians, 60° is equal to π/3 radians. The dead time can be calculated using the formula dead time = time constant * tan(phase lag). Plugging in the values, we get dead time = 5 * tan(π/3) = 5π/12. Therefore, the correct answer is 5π/12.

The correct answer is "Mercury in glass thermometer kept in boiling water". This is because a first-order system is characterized by a single dominant time constant, and in this case, the temperature of the mercury in the thermometer increases exponentially with time as it reaches equilibrium with the boiling water. The other options do not exhibit the characteristics of a first-order system.

The most important advantage of an IC is its extremely high reliability. Integrated circuits are designed to be highly reliable and have a long lifespan. They are manufactured using advanced technologies and undergo rigorous testing to ensure their performance and durability. This high reliability makes ICs suitable for various applications where consistent and dependable operation is crucial, such as in aerospace, medical devices, and telecommunications.

A transportation lag refers to a time delay in the response of a system due to the time it takes for a physical quantity to be transported from one location to another. In this case, since the amplitude ratio for the sinusoidal response of a transportation lag is 1, it means that the amplitude of the output signal is equal to the amplitude of the input signal. Therefore, the correct answer is "transportation lag".

The P-controller has the maximum offset among the given options. A P-controller only considers the present error and adjusts the control signal proportionally. It does not take into account the past or future errors. As a result, when there is a steady-state error, the P-controller cannot eliminate it completely, leading to a non-zero offset. On the other hand, the other controllers mentioned (P-I, P-D, and P-I-D) incorporate integral and derivative terms, which help in reducing or eliminating steady-state errors.

Load cells are specifically designed to measure weight or force. They are commonly used in various industries and applications where accurate weight measurement is required. Load cells work by converting the applied force or weight into an electrical signal, which can then be measured and analyzed. This makes load cells an essential tool for tasks such as weighing scales, industrial weighing systems, material testing, and force monitoring. Therefore, the correct answer for this question is weight.

Iron-constantan thermocouples are commonly used to measure high temperatures, such as the temperature of tempering oil baths maintained at 400°C during heat treatment of steel. Iron-constantan thermocouples are made up of two different metals, iron and constantan, which produce a voltage that is proportional to the temperature difference between the hot and cold junctions. The voltage can then be measured and converted into a temperature reading. Platinum-platinum/rhodium and chromel-alumel thermocouples are not suitable for measuring temperatures as high as 400°C, making iron-constantan the correct choice.

The resolution of an indicating instrument refers to the smallest change in the applied stimulus that will result in a detectable change in the reflection. This means that the instrument is capable of accurately measuring and indicating even the smallest changes in the input stimulus. The other options do not accurately describe the concept of resolution in indicating instruments.

Bode diagrams are generated from the output response of the system subjected to a sinusoidal input. This is because Bode diagrams are used to analyze the frequency response of a system, and sinusoidal inputs are commonly used to measure the system's response at different frequencies. By varying the frequency of the sinusoidal input and observing the corresponding output response, the Bode diagram can be constructed to show the system's gain and phase shift characteristics at different frequencies.

The moving part of a linear variable differential transformer is the core. The core is a magnetic material that moves within the transformer to change the coupling between the primary and secondary windings. This movement of the core allows for the measurement of linear displacement or position.

The Pirani gauge is a type of pressure gauge that is specifically designed for measuring high vacuum levels. It operates by measuring the thermal conductivity of the gas in the vacuum chamber. As the pressure decreases, the thermal conductivity decreases, and the gauge can accurately determine the level of vacuum. Therefore, the correct answer is "high vacuum."

In a stable second order system, the closed loop poles represent the roots of the characteristic equation. For the closed loop poles to be both real and positive, the system must have a positive damping coefficient. This means that the system response will decay over time without oscillating. The positive nature of the poles indicates stability, as the system will settle to its equilibrium state.

The Thomson effect relates the emf generated in a single homogeneous wire to the temperature difference. The effect states that when a temperature gradient is applied across a conductor, a voltage is produced perpendicular to both the temperature gradient and the direction of current flow. This effect is used in thermoelectric devices to convert temperature differences into electrical energy.

Positioning controllers are used for high loads because they are designed to accurately control the position of heavy machinery or equipment. High loads require precise and reliable control to ensure the safety and efficiency of the system. Positioning controllers are capable of handling the high forces and loads associated with heavy machinery, making them suitable for this purpose. They can accurately position and control the movement of the load, ensuring smooth and controlled operation.

Galvanometric recorders give a slow response compared to the other options listed. Galvanometers are devices that measure small electrical currents and are commonly used in instruments such as galvanometric recorders. These recorders use a galvanometer to detect and measure the current or voltage being recorded. However, galvanometers have a limited response speed due to the inertia of the moving parts within the device. Therefore, compared to X-Y recorders, oscillographic recorders, and magnetic recorders, galvanometric recorders have a slower response time.

Magnetic flowmeters operate based on the principle of Faraday's Law of electromagnetic induction, which requires the fluid being measured to have electrical conductivity. Hydrocarbons, such as oil and gas, typically have low electrical conductivity, making them unsuitable for measurement using magnetic flowmeters. Therefore, the correct answer is low electrical conductivity.

A noninverting closed-loop op-amp circuit generally has a gain factor greater than one because the input signal is connected to the noninverting terminal of the op-amp, while the feedback is connected to the inverting terminal. This configuration amplifies the input signal, resulting in an output that is larger in magnitude than the input.

Op-amps used as high- and low-pass filter circuits employ the inverting configuration. In this configuration, the input signal is applied to the inverting terminal of the op-amp, while the feedback resistor is connected between the output and the inverting terminal. This configuration allows the op-amp to provide a phase shift of 180 degrees, which is necessary for the high- and low-pass filter circuits to function properly. By adjusting the values of the resistors and capacitors in the circuit, the cutoff frequency can be set to filter out specific frequency ranges.

A spring loaded diaphragm valve is a typical example of a physical system with underdamped characteristics because it exhibits oscillatory behavior when subjected to disturbances. The spring provides a restoring force, while the diaphragm allows for the movement of fluid. When a disturbance occurs, the valve responds by oscillating around its equilibrium position, gradually damping out over time. This behavior is similar to an underdamped system, where the response overshoots and oscillates before settling down. The other options, such as a thermocouple in a liquid-filled thermowell or a U-tube manometer, do not exhibit the same oscillatory behavior and are not typically associated with underdamped characteristics.

Nichol's chart deals with the relationship between closed loop values and open loop values. It is a graphical representation that helps analyze the stability and performance of a control system. By plotting the closed loop values against the corresponding open loop values, the chart provides insights into the system's frequency response and stability margins. This allows engineers to design and tune controllers to achieve desired system behavior.

The correct answer is DC switch because SCR (Silicon Controlled Rectifier) is a type of semiconductor device that can only control the flow of direct current (DC). It acts as a switch for DC circuits, allowing current to flow when triggered by a control signal. It cannot control the flow of alternating current (AC) or generate square waves, making the options of AC switch and square-wave switch incorrect. Therefore, the SCR can be accurately described as a DC switch.

A system with a double pole at the origin is unstable because the corresponding term in the time domain grows linearly with time. This means that as time progresses, the output of the system will increase at a constant rate. This behavior indicates instability as the system's response is not bounded and will continue to grow indefinitely.

On-off controllers are normally used for low loads because they are designed to switch the control output on or off based on a specific set point. They are not suitable for applications where precise control is required or where there are frequent and rapid changes in the process variable. Instead, on-off controllers are best suited for situations where the load is relatively stable and does not require fine-tuning of the control output.

Fidelity is considered a dynamic characteristic of an instrument because it refers to the ability of the instrument to accurately reproduce the input signal without any distortion or loss of information. It measures the faithfulness of the instrument in accurately representing the input signal's amplitude, frequency, and waveform. A high fidelity instrument will produce an output that closely matches the input signal, while a low fidelity instrument may introduce distortions or inaccuracies. Therefore, fidelity is an important factor in determining the overall quality and accuracy of an instrument's performance.

An ideal operational amplifier has infinite bandwidth, meaning that it can handle a wide range of frequencies without any loss or distortion in the output signal. This is important in applications where a wide range of frequencies need to be amplified accurately. Having infinite bandwidth allows the operational amplifier to work effectively across the entire frequency spectrum.

The P-D controller has the least maximum deviation among the given options. This is because the P-D controller combines proportional control (P) with derivative control (D). The proportional control helps in reducing the steady-state error, while the derivative control helps in reducing the transient response time and minimizing overshoot. By combining these two control actions, the P-D controller is able to achieve better control performance with a smaller maximum deviation compared to the other controllers.

Chromel-constantan thermocouples will give the highest output for the same value of hot and cold junction temperature. This is because chromel has a higher thermoelectric voltage compared to platinum or iron, resulting in a higher output voltage. Constantan is a common material used for the negative leg of thermocouples as it has a relatively low thermoelectric voltage and good stability. Therefore, the combination of chromel and constantan will produce the highest output among the given options.