Current flow in a semiconductor arises from the motion of charge carriers in both the conduction and valence bands. As explained in chapter 4, the mobile charges in the conduction band are electrons and those in the valence band are holes.
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Answer:
The confidence scale represents an ordinal scale of measurement
Explanation:
An ordinal scale or level of measurement is used to measure attributes that can be ranked or ordered, but the interval between the attributes do not have quantitative significance. In this case, the measurement was done on a scale of 1 - 7, with a "1" being; not all that race of defendant has an impact on jury verdicts and a "7" being "very" meaning that race indeed has impact on jury verdicts. Another example can be a survey carried out on the level of customer satisfaction on a particular product, with "1" most dissatisfied and "10 " representing most satisfied. In the first example, it is wrong to say that the difference between 1 being "not at all" and maybe 3 is the same as the difference between 5 and 7 which have different connotations, because the numbers are merely for tagging and not to quantify.
Other levels of measurement include:
1. Nominal: this is the simplest level of measurement and it is simply used to categorize the attributes. Example is taking a survey on gender in the categories of male, female and transgender.
2. Interval: the interval scale is used when the distance between two attributes have meanings but there is no true zero value associated with the scale.
3. Ratio: this combines all the other three levels of measurement and is used to categorize, used to show ranking, has meaningful distances between the attributes and the scale has a true zero point. Example is the measurement of temperature using the celcius scale thermometer, where there is a true zero point at 0°C and the distance between 5°C and 10°C is the same as the distance between 10°C and 15°C.
Answer:
c. A program that offers discounts to libraries and schools ensuring they have affordable access to modern telecommunications and information services.
Explanation:
Federal E-Rate program refers to the Schools and Libraries Program of the Universal Service Fund managed by the Universal Service Administrative Company (USAC) and being directed by the Federal Communications Commission (FCC).
The program offers telecommunications and internet access to schools and libraries in the United States at discounts of between 20% and 90% in order to make the services affordable to them.
The discounts received by each of he beneficiary schools receive which is between the rage of 20% and 90% is determined by the degree of poverty and the urban/rural status of the population or students being served.
In the program, connectivity and maintenance services are provided by the Schools and Libraries Program, while school that applied to the program has to provide other items like software, hardware (e.g. computers), and among other items that will make then to use the connectivity provided.
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Today's radio consists of an antenna, printed circuit board, resistors, capacitors, coils and transformers, transistors, integrated circuits, and a speaker. All of these parts are housed in a plastic case. An internal antenna consists of small-diameter insulated copper wire wound around a ferrite core.
Answer:
-6.326 KJ/K
Explanation:
A) the entropy change is defined as:
In an isobaric process heat (Q) is defined as:
Replacing in the equation for entropy
m is the mass and Cp is the specific heat of R134a. We can considerer these values as constants so the expression for entropy would be:
Solving the integral we get the expression to estimate the entropy change in the system
The mass is 5.25 Kg and Cp for R134a vapor can be consulted in tables, this value is
We can get the temperature at the beginning knowing that is saturated vapor at 500 KPa. Consulting the thermodynamic tables, we get that temperature of saturation at this pressure is: 288.86 K
The temperature in the final state we can get it from the heat expression, since we know how much heat was lost in the process (-976.71 kJ). By convention when heat is released by the system a negative sign is used to express it.
With clearing for T2 we get:
Now we can estimate the entropy change in the system
The entropy change in the system is negative because we are going from a state with a lot of disorder (high temperature) to one more organize (less temperature. This was done increasing the entropy of the surroundings.
b) see picture.