Metrology Quiz 2 And 3

The angle dekkor is used for the measurement of angles. It is a precision instrument that is specifically designed for measuring angles in various applications. The angle dekkor typically consists of a circular scale with a pointer that can be rotated to measure the angle between two lines or surfaces. It is commonly used in fields such as engineering, construction, and manufacturing for accurate angle measurements.

Limit gauges are used to check if the component dimension lies within permissible limits. These gauges are designed with specific tolerances to ensure that the component being measured is within the acceptable range of dimensions. By using limit gauges, manufacturers can quickly determine if a component is within the specified limits or if it needs to be rejected. This helps to maintain quality control and ensure that only components that meet the required dimensions are used in the final product.

The numbers 7 and 8 in the hole and shaft assembly 40 H7/d8 indicate the tolerance grade. Tolerance grade refers to the allowable deviation from the specified dimension. In this case, the hole has a tolerance grade of H7, which means that the actual dimension of the hole can deviate by a certain amount from the specified dimension. Similarly, the shaft has a tolerance grade of d8, indicating its allowable deviation. These tolerance grades ensure that the parts can fit together properly while allowing for manufacturing variations.

Unilateral tolerance refers to the acceptance and respect for diverse beliefs, opinions, and behaviors from only one side or party. It means that one group or individual is willing to tolerate and respect the views and actions of others, even if they do not reciprocate the same tolerance. Therefore, the statement "unilateral tolerance having its viability in one side only" is true, as it accurately describes the concept of unilateral tolerance.

The most important parameter in metrology is length. Length is a fundamental measurement that is used as a basis for many other measurements. It is crucial in various fields such as engineering, construction, and manufacturing. Accurate and precise length measurements are essential for ensuring the quality and reliability of products and processes. Additionally, length is a fundamental parameter in scientific research and experimentation.

The correct answer is "Total tolerance is in both the directions." This means that bi-lateral tolerance refers to the tolerance that is allowed in both positive and negative directions from the nominal dimension. In other words, it is the range within which the actual dimension of a component can vary in either direction and still be considered acceptable.

When two dissimilar metals are joined together to form two junctions, a net electromotive force (emf) is generated. This phenomenon is known as the Seebeck effect. The Seebeck effect is the production of an emf in a circuit consisting of two different metals when there is a temperature difference between the junctions. This effect is used in thermocouples to measure temperature differences. Therefore, the statement is true.

The Mc Leod Gauge works under the principle of Boyle's Law. Boyle's Law states that the pressure of a gas is inversely proportional to its volume, provided the temperature remains constant. In the case of the Mc Leod Gauge, it measures pressure by using a gas-filled chamber with a known volume. As the pressure increases, the volume of the gas decreases. By measuring the change in volume, the pressure can be determined according to Boyle's Law. Therefore, the correct answer is Boyle's Law.

An angle dekkor is indeed a small variation of an autocollimator. Autocollimators are optical instruments used for measuring small angular deviations and are commonly used in metrology and alignment applications. An angle dekkor is a specific type of autocollimator that is designed to measure the angle between two surfaces or objects. It typically consists of a telescope and a reticle or scale that allows for precise angle measurements. Therefore, the statement "an angle dekkor is a small variation of an autocollimator" is true.

The performance of a spirit level is indeed governed by the geometrical relationship between the bubble and two references. The bubble in a spirit level is used to determine if a surface is level or plumb. When the bubble is centered between the two references, it indicates that the surface is level or plumb. The position of the bubble in relation to the references is crucial for accurate measurements and ensures the level's performance. Therefore, the statement is true.

The maximum angle that can be set using a sine bar is limited to 45 degrees. This is because a sine bar is a precision measuring tool that is used to set up or measure angles. It consists of a bar with two accurately machined cylindrical surfaces that are parallel to each other. By placing the workpiece on the sine bar and adjusting its position, the desired angle can be achieved. However, the maximum angle that can be set is limited to 45 degrees due to the design and construction of the sine bar.

The statement is true because the variance is a measure of how spread out the data is in a distribution. It is calculated by taking the average of the squared differences between each data point and the mean. The square of the standard deviation is used to calculate the variance, making the statement correct.

A good instrument refers to a reliable and accurate tool or device. However, if it is used in an unintelligent way, meaning it is not operated or utilized properly, it can produce incorrect or erroneous results. This statement highlights the importance of using instruments correctly to obtain accurate data or outcomes.

The ISO system of limit and fits specifies 18 grades of tolerances.

Geometric tolerance refers to the allowable deviation from a specified geometric form or relationship. In this context, perpendicularity is a type of geometric tolerance that defines the allowable deviation of a surface or axis from a perfect 90-degree angle. It ensures that two surfaces or axes are perpendicular within a certain tolerance range. Therefore, the correct answer is geometric tolerance.

The statement is true because an allowance refers to the intentional difference between the maximum material limit (MML) of the lower limit of hole size (LLH) and the higher limit of shaft size (HLS) of two mating parts. This allowance is necessary to ensure proper fit and functionality between the parts.

A pyrometer is a contactless temperature measurement device that is used to measure high temperatures. It works based on the principle of detecting the thermal radiation emitted by an object. A pyrometer can measure temperatures ranging from several hundred degrees Celsius to several thousand degrees Celsius. It is commonly used in industrial applications such as metalworking, glass manufacturing, and furnace temperature monitoring. Unlike other options listed, a pyrometer does not require physical contact with the object being measured, making it suitable for measuring temperatures in hazardous or hard-to-reach environments.

The statement suggests that H9/e9 is running fit with greater clearances, meaning there is more space between the parts that are fitting together. It also states that there are no special requirements for fit accuracy. Therefore, the statement implies that H9/e9 can function properly even with the increased clearances and does not need to meet any specific fit accuracy standards.

In a Pirani Gauge, the pressure is related to the thermal conductivity of the gas. The Pirani Gauge works by measuring the change in resistance of a heated wire as the gas molecules transfer heat away from it. The rate at which the gas molecules transfer heat is directly proportional to the thermal conductivity of the gas. Therefore, by measuring the change in resistance of the wire, the pressure of the gas can be determined based on its thermal conductivity.

MML stands for Maximum Material Limit. In engineering, it refers to the specified dimensions that define the upper limit for a hole and the lower limit for a shaft. The lower limit of a hole represents the smallest acceptable size for the hole, while the higher limit of a shaft represents the largest acceptable size for the shaft. Therefore, the correct answer is "lower limit of hole and higher limit of shaft."

A Pirani Gauge is a device used for measuring low pressure in the order of 0.001 torr. It operates based on the principle that the thermal conductivity of gas decreases as the pressure decreases. The gauge consists of a heated wire or filament that is exposed to the gas being measured. As the gas pressure decreases, the heat dissipation from the filament decreases, causing a change in its resistance. This change in resistance is then converted into a pressure measurement. Therefore, the Pirani Gauge is the correct choice for measuring low pressures in the given range.

Deviation represents the departure of the observed readings from the arithmetic mean of the group of readings. It measures the difference between each individual reading and the mean, indicating how much each reading deviates from the average value. By calculating the deviation, we can understand the spread or dispersion of the data points around the mean, providing insights into the variability or consistency of the readings.

In the shaft basis system, the upper deviation of the shaft is 0. This means that the shaft is perfectly aligned with the upper limit of the specified dimension. In other words, there is no allowance for any additional size or clearance in the upper direction. Therefore, the statement "True" is correct.

The gauge factor refers to the ratio of the change in resistance to the total resistance due to strain in a gauge. It is a measure of the sensitivity of the gauge to strain and is commonly used in the field of strain measurement.

This statement is true because a pressed fit refers to the assembly of two parts where one is inserted into the other with an interference or tight fit. In this case, H7/p6 indicates that the hole (H7) is slightly larger than the shaft (p6), ensuring an interference fit. Therefore, the statement is correct in stating that H7/p6 is a pressed fit with guaranteed interference.

H11/a11 is a type of clearance fit. In clearance fits, the maximum shaft size (H11) is always smaller than the minimum hole size (a11). This allows for easy assembly and disassembly of the parts with a small amount of clearance between them. Therefore, the given statement is true.

A loose running fit refers to a type of fit where there is a small amount of clearance between the mating parts, allowing for easy movement and assembly. In this case, the class of fit H7/d9 indicates that the hole (diameter 9) is slightly larger than the shaft (diameter 7), resulting in a loose fit. This type of fit is commonly used when there is a need for quick assembly and disassembly, or when there is a requirement for easy movement between the parts.

In a bilateral system, it is not possible to retain the same fit when tolerance is varied. This means that if the tolerance is adjusted or changed, the fit between the components or parts in the system will also change. The term "bilateral" refers to a system where both sides or aspects are considered, and in this case, it implies that the fit is affected on both sides when the tolerance is altered. Therefore, the fit cannot remain consistent or unchanged when the tolerance is varied in a bilateral system.

H7/h6 is a tolerance class used in engineering to ensure precise guiding of machines, such as roller guides. The H7 tolerance class represents a hole or shaft with a slightly larger diameter, while the h6 tolerance class represents a slightly smaller diameter. By using these tolerance classes, the fit between the shaft and the hole can be controlled to provide accurate and smooth movement, which is crucial for the precise guiding of machines. Therefore, the statement that H7/h6 is used for precise guiding of machines such as roller guides is true.

NO GO gauges are designed for minimum passability. This means that these gauges are used to ensure that a part or component does not pass through or fit into a specific area or opening. The purpose of using NO GO gauges is to ensure that there is a minimum allowable clearance or tolerance, and any part or component that does not meet this requirement is considered out of specification. Therefore, the correct answer is "For minimum passability."

Slip gauge is not an example of a line standard. Slip gauges are used as reference standards for measuring the dimensions of objects in engineering and machining. They are typically used for checking the accuracy of micrometers and other measuring instruments. Line standards, on the other hand, are used for measuring straightness or alignment of objects. Therefore, the statement that slip gauge is an example of a line standard is false.

The cross section of a bourdon tube is elliptical. This shape allows for better flexibility and sensitivity to pressure changes. The elliptical cross section ensures that the tube can expand and contract uniformly in response to pressure, allowing for accurate measurement. Rectangular or triangular shapes would not provide the same level of flexibility, while a circular shape would not allow for as much expansion and contraction in response to pressure changes.

The hole basis system is widely accepted because during assembly, the system gives full freedom to the operators. This means that the operators have the flexibility to adjust and align the components according to their preferences and requirements. This allows for easier assembly and reduces the chances of errors or misalignments. The system's ability to provide full freedom during assembly makes it a preferred choice for many applications.

The longer the sine bar, the better the accuracy because a longer sine bar provides a larger measuring base, which reduces errors caused by small variations in the angle of the workpiece. This increased base length allows for more precise measurements and improved accuracy in determining the angle of the workpiece.

The correct answer is "None of the above" because radiation pyrometers are used to measure high temperatures, typically above 1000 degrees Celsius. The given temperature ranges (0-200, 250-500, and 500-1000) are relatively low and do not fall within the typical range of a radiation pyrometer.

The given statement is not clear or coherent, making it difficult to determine its meaning. Therefore, an explanation cannot be provided.

The statement is false because fundamental deviation refers to the algebraic difference between the size of a component and its basic size, not the maximum difference. The fundamental deviation can be positive or negative, indicating whether the component is larger or smaller than the basic size. Therefore, the maximum difference is not necessarily the same as the fundamental deviation.

A compound sine plate is a specialized instrument that is capable of measuring compound angles. It is designed with two sets of sine bars that can be adjusted independently, allowing for the measurement of angles in two different planes simultaneously. This makes it suitable for measuring compound angles, which are angles that occur in more than one plane. The other instruments mentioned, such as the sine centre and compound surface plate, are not specifically designed for measuring compound angles.

Bonded gauges are strain gauges that are directly bonded to the surface of the object being measured. In this case, an unmounted gauge wire is stretched between two mechanical points and bonded to the surface. As tension is applied to the wire, it experiences strain, which is measured by the bonded gauge. This allows for accurate measurement of tension in the wire. Unbonded gauges, plug gauges, and ring gauges are not suitable for measuring tension in this manner.

Manometers measure unknown pressure by balancing the unknown force produced by the pressure against a known force. This is done by using a liquid column or a pointer to indicate the pressure. The known force is typically provided by a weight or a spring, which is adjusted until it balances the unknown force. This balance allows for the accurate measurement of the pressure.

A thermopile is a device that consists of multiple thermocouples connected in series. Each thermocouple generates a small voltage when there is a temperature difference across it. By connecting multiple thermocouples in series, the voltage generated by each individual thermocouple adds up, resulting in a higher overall voltage output. This allows thermopiles to generate larger electrical signals in response to temperature differences, making them useful in applications such as temperature measurement and energy harvesting.

The statement is false. H8/g6 is not a running fit with greater clearances for accurate guiding of shafts. H8/g6 is actually an interference fit, which means that the shaft is intentionally larger than the hole to create a tight fit. This type of fit is used when a secure and rigid connection is required between the shaft and the hole.

The statement "C11/h11 is an interference fit" is true. An interference fit refers to a type of fit where the dimensions of the mating parts are intentionally designed to have an overlap, resulting in a tight and secure connection. In this case, the dimensions of the parts C11 and h11 are such that they create an interference fit when assembled together. This means that the parts will have a tight and secure connection, ensuring proper alignment and preventing any relative movement between them.

When an elastic member is used in conjunction with a strain gauge, it is called a load cell. A load cell is a transducer that converts force or weight into an electrical signal. It measures the deformation or strain of the elastic member caused by the applied load, which is then converted into an electrical output signal proportional to the force or weight being measured. Load cells are commonly used in various applications such as weighing scales, industrial automation, and force measurement systems.

The incorrect zero setting of the pointer can cause systematic errors in a bourdon tube pressure gauge. This means that when the pressure gauge is at zero pressure, the pointer may not align correctly with the zero mark on the scale. As a result, all subsequent readings will be offset by this incorrect zero setting, leading to inaccurate measurements.

A load cell is essentially a strain gauge because a strain gauge is a device that measures the strain or deformation of an object. In the case of a load cell, the strain gauge is used to measure the amount of force or load applied to the cell. As the load is applied, the strain gauge undergoes deformation, which changes its electrical resistance. This change in resistance is then measured and converted into a corresponding load value. Therefore, a strain gauge is the most appropriate choice for a load cell as it accurately measures the strain and converts it into a usable signal.

The sensitivity of a spirit level refers to its ability to detect small changes in level. The radius of the curvature of the bubble tube affects the sensitivity of the spirit level. A smaller radius of curvature means a more sensitive level, as the bubble will move more quickly in response to changes in level. The width of the bubble and the accuracy of the base plate may affect the overall performance of the spirit level, but they do not directly determine its sensitivity.

A bimetallic strip thermometer works on the principle that different metals expand and contract at different rates when subjected to temperature changes. The strip is made of two different metals with different coefficients of thermal expansion. As the temperature changes, the metals expand or contract, causing the strip to bend. This bending is then used to indicate the temperature on a calibrated scale. Therefore, the given statement is true.

Tolerances are given to parts in order to reduce the cost of the assembly. By allowing for small variations in the dimensions of the parts, manufacturers can avoid the need for precise and expensive machining processes. This allows for greater flexibility in production and reduces the overall cost of manufacturing the assembly.

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