The question asks about the charge carriers responsible for current in an intrinsic semiconductor at room temperature. We need to understand the basic conduction mechanism in intrinsic semiconductors.
D) holes and electrons both — At room temperature, thermal energy breaks covalent bonds in an intrinsic semiconductor, creating free electrons in the conduction band and holes in the valence band. Both these charge carriers are mobile and contribute to the electric current.
This problem involves simplifying a Boolean expression using the fundamental laws of Boolean algebra. Specifically, we will use the Distributive Law and the Complement Law.
Thus, the simplified expression is \(A\).
Correct Option: B) The expression \(AB + AB'\) simplifies to \(A\).
The question asks to identify the digital device that takes one input and distributes it to many outputs. We need to understand the basic functions of each option provided.
Correct Option: B) Demultiplexer — A demultiplexer (DEMUX) is a combinational logic circuit that takes a single data input and routes it to one of several output lines. The specific output line is chosen by applying a binary code to the select input lines. Therefore, it has one input and many outputs.
The question asks about the number of bits used in ASCII (American Standard Code for Information Interchange). This is a fundamental concept in computer science and data representation. We need to recall the standard definition of ASCII.
A) 7
The original and standard ASCII encoding uses 7 bits to represent each character, allowing for 128 unique characters.
The question asks for an alternative expression for Poise, which is the CGS unit of dynamic viscosity. To solve this, we need to recall the definition of dynamic viscosity and its formula, then express it in terms of fundamental CGS units (dyne, cm, s).
Definition of Dynamic Viscosity: Dynamic viscosity \( \eta \) is defined by Newton's law of viscosity, which states that the shear stress \( au \) in a fluid is directly proportional to the velocity gradient \( \frac{du}{dy} \).
\[ au = \eta \frac{du}{dy} \]Rearrange for Viscosity: We can rearrange this formula to express viscosity:
\[ \eta = \frac{ au}{\frac{du}{dy}} \]Units of Shear Stress \( au \): Shear stress is defined as force per unit area. In the CGS system, force is measured in dynes (dyne) and area in square centimeters (cm²).
\[ \text{Unit of } au = \frac{\text{Force}}{\text{Area}} = \frac{\text{dyne}}{\text{cm}^2} \]Units of Velocity Gradient \( \frac{du}{dy} \): Velocity gradient is the change in velocity (\(du\)) with respect to the change in distance (\(dy\)). In the CGS system, velocity is in cm/s and distance is in cm.
\[ \text{Unit of } \frac{du}{dy} = \frac{\text{Velocity}}{\text{Distance}} = \frac{\text{cm/s}}{\text{cm}} = \frac{1}{\text{s}} \]Substitute Units into Viscosity Formula: Now, substitute the units of shear stress and velocity gradient back into the formula for viscosity \( \eta \):
\[ \text{Unit of } \eta = \frac{\text{Unit of } au}{\text{Unit of } \frac{du}{dy}} = \frac{\frac{\text{dyne}}{\text{cm}^2}}{\frac{1}{\text{s}}} \]Simplify the Expression: Simplify the complex fraction:
\[ \text{Unit of } \eta = \frac{\text{dyne}}{\text{cm}^2} \times \text{s} = \frac{\text{dyne} \cdot \text{s}}{\text{cm}^2} \]Conclusion: Therefore, Poise, the CGS unit of dynamic viscosity, can be expressed as dyne-s/cm².
Correct Option: D) Dyne-s/cm²
The question asks about the number of phases present in a typical soil mass. Soil is a complex material, and understanding its composition is fundamental in geotechnical engineering. We need to identify the distinct components that make up a soil sample.
A) 3. A soil mass is typically considered a three-phase system consisting of solid particles, water, and air.
This question tests the understanding of the primary function and suitability of bolts in structural connections. Bolts are primarily designed to resist tensile forces due to their geometry and the way they are tightened.
Correct Option: C) Axial tension. Bolts are most suitable to carry axial tension because their design and installation (tightening) inherently induce and allow them to effectively resist tensile forces along their longitudinal axis.
The spherical shape of liquid droplets is a classic example of surface tension at play. Liquids tend to minimize their surface area due to cohesive forces between their molecules. For a given volume, a sphere has the minimum surface area, which is why droplets adopt this shape.
Correct Option: B) High surface tension
The question asks to identify the method of orienting a plane table when two inaccessible points are involved. This is a specific problem in plane table surveying that requires a particular technique for orientation.
D) Two-point problem — This is a specific method in plane table surveying used to orient the plane table and locate its position on the map when only two well-defined points, whose positions are already plotted on the map, are available. These points can be inaccessible, making this the correct method for the scenario described.
The question asks to identify the probability distribution for which 'most likely time (m)' is the mode. This refers to distributions commonly used in project management techniques like PERT (Program Evaluation and Review Technique), where activity durations are often modeled. The mode represents the most frequent or most likely value in a distribution.
The Beta distribution is widely used in PERT (Program Evaluation and Review Technique) to model the duration of activities. In this context, the 'most likely time' (m) is indeed the mode of the Beta distribution, representing the peak of its probability density function.