This question asks about the number of valence electrons in a pure semiconductor. To answer this, we need to recall the definition of a semiconductor and the typical elements used as intrinsic semiconductors.
C) 4 — Pure semiconductors like Silicon and Germanium are Group 14 elements, meaning they have 4 valence electrons. These 4 electrons are crucial for their characteristic bonding and electrical properties.
To determine which basic logic gates can construct an Exclusive-OR (XOR) gate, we need to recall the Boolean expression for XOR and then see how it can be implemented using combinations of AND, OR, and NOT gates.
This expression means "A AND NOT B" OR "NOT A AND B".
Correct Option: C) AND gates, OR gates, and NOT gates
The question asks for the term describing the process of combining an Audio Frequency (AF) signal with Radio Frequency (RF) waves. This is a fundamental concept in communication systems.
A) modulation is the correct term for mixing an AF signal with RF waves to transmit information. The AF signal modifies a characteristic of the RF carrier wave.
The question asks for the main advantage of Frequency Modulation (FM) over Amplitude Modulation (AM). We need to compare the characteristics of both modulation techniques, particularly regarding their susceptibility to noise and signal quality.
Correct Option: D) the elimination of noises
Frequency modulation (FM) is inherently more immune to noise than amplitude modulation (AM). In FM, the information is carried by changes in the frequency of the carrier wave, while its amplitude remains constant. Most common types of noise (e.g., atmospheric noise, electrical interference) primarily affect the amplitude of a signal. An FM receiver uses a limiter circuit that removes any amplitude variations from the received signal, effectively eliminating much of the noise before demodulation. This leads to a much clearer and higher-fidelity signal compared to AM.
The question asks about the nature of a material when its modulus of elasticity is zero. We need to understand the definition of the modulus of elasticity and how it relates to a material's deformation under stress.
Correct Option: D) Plastic — A material with a zero modulus of elasticity means that it offers no resistance to deformation. Even a tiny stress would cause infinite or permanent deformation. This behavior is characteristic of a perfectly plastic material, which deforms permanently without recovering its original shape.
The question asks about the possible range of water content in soil. Water content (or moisture content) is a fundamental property in soil mechanics, defined as the ratio of the weight of water to the weight of solid particles in a soil sample. Understanding this definition is key to determining its possible values.
where \(W_w\) is the weight of water and \(W_s\) is the weight of soil solids.
A) Greater than 100% - As explained above, if the weight of water in a soil sample exceeds the weight of the solid particles, the water content will be greater than 100%. This is common in highly plastic clays, organic soils, or slurries.
The question asks about the maximum percentage of moment redistribution allowed in Reinforced Cement Concrete (RCC) beams. This is a specific code provision related to the design of indeterminate structures, primarily covered by Indian Standard (IS) codes like IS 456:2000.
C) 30% is the maximum percentage of moment redistribution allowed in RCC beams as per IS 456:2000.
This question pertains to the calculation of bending stresses in structural members, specifically distinguishing between compressive and tensile stresses. The key lies in understanding how the presence of holes (like rivet or bolt holes) affects the effective area resisting these different types of stresses.
Bending Compressive Stress: When a member is subjected to bending, the compression zone tends to buckle. Even if there are holes in the compression zone, the material around the holes can still contribute to resisting compression due to local bearing and redistribution of stresses. Therefore, for calculating bending compressive stress, the gross area of the section is generally considered.
Bending Tensile Stress: In the tension zone, any discontinuity like a hole reduces the effective cross-sectional area available to resist the tensile forces. The material removed by the hole cannot carry tension. Therefore, for calculating bending tensile stress, the net area (gross area minus the area of holes) is considered.
Summary: Compressive stresses are calculated based on the gross area, while tensile stresses are calculated based on the net area.
Correct Option: B) Gross area and net area
The question asks about the ideal properties of a liquid used in manometers. Manometers are devices used to measure pressure differences. The choice of liquid depends on the range of pressure to be measured and the desired sensitivity.
Given the options, the most crucial property for a liquid in a manometer to measure a reasonable range of pressures efficiently is high density.
B) High density
A high-density liquid (like mercury) is preferred in manometers for several reasons. It allows for the measurement of large pressure differences with a relatively small column height, making the manometer compact and practical. If the density were low, the column height would become excessively large for significant pressure differences, making the device unwieldy.
The question asks to identify the instrument generally used for baseline measurements in surveying. Baseline measurements require high precision and minimal error due to thermal expansion or contraction. We need to evaluate the properties of each given option to determine which one best suits this requirement.
D) Invar tape is generally used for baseline measurements because its very low coefficient of thermal expansion ensures high accuracy by minimizing length changes due to temperature fluctuations, which is crucial for fundamental survey lines.