Solution:
Given :
atomic radius, r = 0.1363nm = 0.1363×10⁻⁹m
atomic wieght, M = 95.96
Cell structure is BCC (Body Centred Cubic)
For BCC, we know that no. of atoms per unit cell, z = 2
and atomic radius, r =[tex]\frac{a\sqrt{3} }{4}[/tex]
so, a = [tex]\frac{4r}{\sqrt{3}}[/tex]
m = mass of each atom in a unit cell
mass of an atom = [tex]\frac{M}{N_{A} }[/tex],
where, [tex]N_{A}[/tex] is Avagadro Number = 6.02×10^{23}
volume of unit cell = a^{3}
density, ρ = [tex]\frac{mass of unit cell}{volume of unit cell}[/tex]
density, ρ = [tex]\frac{z\times M}{a^{3}\times N_{A}}[/tex]
ρ = [tex]\frac{2\times 95.95}{(\frac{4\times 0.1363\times 10^{-9}}{\sqrt{3}})^{3}\times (6.23\times 10^{23})}[/tex]
ρ = 10.215gm/[tex]cm^{3}[/tex]
Describe harmful effect associated with extraction of Aluminum, Gold and Copper. Discuss each individually.
Answer:
Harmful effect associated with extraction of Aluminum, Gold and Copper are:
During the melting of aluminium there is a released of per fluorocarbon are more harmful than carbon dioxide in the environment as they increased the level of green house gases and cause global warming. The process of transforming raw material into the aluminium are much energy intensive.
Gold mining industries destroyed land scopes and increased the amount of toxic level in the environment and they also dump there toxic waste in the natural water bodies, which increased the level of water pollution in the environment.
Copper mining causes the health problems like asthma and problem in respiratory system because of the inhalation of silica dust. It also increased the level of sulfur diode in the environment which cause acid rain and destroyed various trees and buildings in the nature.
A force of 250 N is acting on an area of 2 m2. The pressure is therefore:
Answer:
125 Pascal
Explanation:
We know that
[tex]Pressure=\frac{Force}{Area}[/tex]
Applying given values we get
[tex]Pressure=\frac{250N}{2m^{2}}[/tex]
[tex]Pressure=125\frac{N}{m^{2}}[/tex]
Pressure = 125 Pascal
What is the thermal efficiency of this regeneration cycle in terms of enthalpies and fractions of total flow?
Answer:
[tex]\eta =\dfrac{(h_3-h_4)-(h_2-h_1)}{(h_3-h_5)}[/tex]
Explanation:
generally regeneration of cycle is used in the case of gas turbine. due to regeneration efficiency of turbine is increased but there is no effect on the on the net work out put of turbine.Actually in regeneration net heta input is decreases that is why total efficiency increase.
Now from T-S diagram
[tex]W_{net}=W_{out}-W_{in}[/tex]
[tex]W_{net}=(h_3-h_4)-(h_2-h_1)[/tex]
[tex]Q_{in}=h_3-h_5[/tex]
Due to generation [tex](h_5-h_2)[/tex] amount of energy has been saved.
[tex]Q_{generation}=Q_{saved}[/tex]
So efficiency of cycle [tex]\eta =\frac{W_{net}}{Q_{in}}[/tex]
[tex]\eta =\dfrac{(h_3-h_4)-(h_2-h_1)}{(h_3-h_5)}[/tex]
Effectiveness of re-generator
[tex]\varepsilon =\dfrac{(h_5-h_2)}{(h_4-h_2)}[/tex]
So the efficiency of regenerative cycle
[tex]\eta =\dfrac{(h_3-h_4)-(h_2-h_1)}{(h_3-h_5)}[/tex]
The total energy of a system remains unchanged during a cycle. a)- True b)- False
Answer: True
Explanation: It is correct that during a cycle the energy of the system remains unchanged. Total energy consist of the initial energy and the final energy in a system and both remain equal in a system whether they are in cycle or not ans also according to the law of conservation of energy ,total energy cannot be destroyed or created. Thus the while a cycle goes on energy will remain the same.
The slope of a moment diagram is the load. a)-True b)-False
Answer:
true.
Explanation:
but i am not 100% sure
Why metals are good thermal conductors, but polymers are not?
Answer: Metals are good thermal conductors because they have close packaged metal ions in their lattice structure but in polymers they have discontinuous structure which make them poor as a conductor.
Explanation: Metals are considered as good thermal conductors because of their lattice structure which has tightly packed ions in it. In the outer shell of atoms the electrons are free to move and thus conduct the electricity but for the polymers, they have a different structure as compared to metals thus it makes it difficult for a polymer to conduct electricity due to high number of discontinuous particle chains. Therefore metals are good conductors , but polymers are not.
Consider a Carnot cycle executed in a closed system with 0.0058 kg of air. The temperature limits of the cycle are300 K and 940 K, and the minimum and maximum pressures that occur during the cycle are20 kPa and 2,000 kPa. Assuming constant specific heats, determine the net work output per cycle.
Answer:0.646 KJ
Explanation:
Using First law for cycle
[tex]\sum Q=\sum W[/tex]
[tex]\sum Q=Q_{1-2}+Q_{3-4}[/tex]
For adiabatic process heat transfer is zero and for isothermal process
d(Q)=d(W)
[tex]Q_{1-2}=mRT_1\ln {\frac{P_1}{P_2}}[/tex]
Given [tex]P_1=2000KPa[/tex]
[tex]P_3=20KPa[/tex]
[tex]\left (\frac{T_2}{T_3}\right )^{\frac{\gamma }{\gamma -1}[/tex]=[tex]\left (\frac{P_2}{P_3}\right )}[/tex]
[tex]P_2=1089.06K[/tex]
[tex]Q_{1-2}=0.0058\dot 0.287\dot 940\ln \frac{2000}{1089.06}[/tex]=[tex]0.95KJ[/tex]
[tex]Q_{3-4}=mRT_2\ln {\frac{P_3}{P_4}}[/tex]
[tex]\left (\frac{T_1}{T_4}\right )^{\frac{\gamma }{\gamma -1}[/tex]=[tex]\left (\frac{P_1}{P_4}\right )}[/tex]
Now we have to find [tex]P_4=36.72KPa[/tex]
[tex]Q_{3-4}=0.0058\dot 0.287\dot 300\ln \frac{20}{36.72}[/tex]=[tex]-0.30341KJ[/tex]
[tex]Q_{net}=Q_{1-2}+Q_{3-4}[/tex]
[tex]Q_{net}=0.95-0.303=0.646KJ[/tex]
[tex]Q_{net}=W_{net}=0.646KJ[/tex]
Beam carries loads that are parallel to ts longitudinal axis. a)-True b)-False
Answer:
Explanation:
b) This statement is False
A beam is a structural member that carries load in the direction perpendicular to its longitudinal axis or we can say that a beam is subjected to transverse loads. Generally, all loads act in the vertical direction, either upward or downward, i.e., remain perpendicular to its longitudinal axis
A U-tube manometer with both ends open, contains 0.35 m of oil on its left limb with an interface with water below it. If the water level on the right limb is 0.28 m above the interface, what is the SG of oil?
Answer:
0.8
Explanation:
Given:
[tex]h_{oil}[/tex] = 0.35m
[tex]h_{water}[/tex] = 0.28m
Equating the pressure in the manometer at both ends
we have
Pressure at the left limb = Pressure at right limb
[tex]\rho_{oil} gh_{oil}=\rho_{water} gh_{water}[/tex]
substituting the values in the above equation, we get
[tex]\rho_{oil}\times g\times 0.35=\rho_{water}\times g\times 0.28[/tex]
[tex]\frac{\rho_{oil}}{\rho_{water}} =\frac{ 0.28}{0.35}[/tex]
[tex]\frac{\rho_{oil}}{\rho_{water}} =0.8[/tex]
we know that specific gravity is defined as the ratio of the density of the fluid with respect to the density of water
thus, SG of oil = 0.8
A semiconductor is a solid substance that has a conductivity between that of an insulator and that of most metals. (True , False )
The answer is : True
What are the three basic types of positive displacement pumps.
Answer:
a) reciprocating pump
b) rotary pump
c) linear pump
Explanation:
Positive displacement pump has enlarged cavity on the suction side and decreasing cavity on the discharge side and in positive displacement pump
the amount of fluid captured and inside and then discharged is same.
There are three type of positive displacement pump
a) reciprocating pump is the pump which two valve during suction outlet valve is closed and for delivery the inlet valve is closed and pump is used for discharge
b) rotary pump fluid move with the help of rotary the rotation of rotary displaces water.
c) linear pump is the pump in which displacement is linear rope and chain pump is example of this type of pump.
A particle is moving along a straight line with an initial velocity of 6 m/s when it is subjected to a deceleration of a- (-1.5v12) m/s2, where v is in m/s. Determine how far it travels before it stops. How much time does this take?
To find the distance traveled by the particle before it stops, one would need to solve a differential equation involving the deceleration a = -1.5v^2, which is beyond high school level calculations, thus an exact solution is not provided here.
Explanation:A particle is moving along a straight line with an initial velocity of 6 m/s when it is subjected to a deceleration of a = -1.5v^2 m/s2, where v is in m/s. To determine how far it travels before it stops, and how much time this takes, we need to integrate with respect to the velocity. A straightforward way to do this calculation would be to separate variables and integrate both sides from the initial to the final condition (which is zero velocity).
However, the given problem does not provide a straightforward formula for the distance covered or time taken, as it requires solving a differential equation. The integration leads to functions of time and distance in terms of an initial velocity and acceleration function, not a final analytical result. Due to the lack of a specific formula to solve this question in the provided references, we cannot determine the exact distance traveled or time taken for the particle to come to a stop without additional calculations beyond the high school level.
Find the dimensions of a circular cross section steel bar subjected to tension by a force N 20000 N in two hypotheses: a) the maximum allowable stress is 150 N/mm2, b) the maximum acceptable strain is 0.0005. Take E 207GPa
Answer:
d = 13 mm
d = 15.68 mm
Explanation:
Given data
force = 20000 N
stress = 150 N/mm²
strain = 0.0005
E = 207 GPa
Solution
we know stress = force / area
so 0.0005 = 20000 / area
area = [tex]\pi[/tex]/4 × d²
put the area in stress equation and find out d
d² = 4×force / [tex]\pi[/tex] ×stress
d² = 4× 20000 / [tex]\pi[/tex] ×150
d = [tex]\sqrt{ 4× 20000 / [tex]\pi[/tex] ×150}[/tex]
d = 13 mm
and now we know starin = stress / E
same like stress we find d here
d = [tex]\sqrt{ 4× 20000 / [tex]\pi[/tex] ×0.0005×207×10³ }[/tex]
so d = 15.68 mm
Answer:
a). d = 13 mm
b). d = 16 mm
Explanation:
a). Given :
Force = 20000 N
Maximum stress, σ = 150 N/[tex]mm^{2}[/tex]
Therefore, we know that that
σ = [tex]\frac{Force}{area}[/tex]
150 = \frac{Force}{\frac{pi}{4}\times d^{2}}
150 = \frac{20000}{\frac{pi}{4}\times d^{2}}
[tex]d^{2}[/tex] = 169.76
d = 13.02 mm
d [tex]\simeq[/tex] 13 mm
b). Given :
Strain, ε = 0.0005
Young Modulus, E = 207 GPa
= 207[tex]\times[/tex][tex]10^{3}[/tex] MPa
Therefore we know that, Stress σ = E[tex]\times[/tex]ε
= 207[tex]\times[/tex][tex]10^{3}[/tex][tex]\times[/tex]0.0005
= 103.5 N/[tex]mm^{2}[/tex]
We know that
σ = [tex]\frac{Force}{Area}[/tex]
103.5 = [tex]\frac{Force}{\frac{pi}{4}\times d^{2}}[/tex]
[tex]d^{2}[/tex] = 246.27
d = 15.69 mm
d [tex]\simeq[/tex]16 mm
Extensive property means and explain Example of extensive property.
Answer: Extensive property is a property of matter that changes as the amount of matter changes.
Explanation: An extensive property is explained as a property changes as the amount of matter changes and it is measured without any chemical change occurring. For example mass and volume are extensive properties. As more matter is added to a system, mass and volume both changes. It basically do not depend on the size of the system, nor the amount present in the system.
The relatonship between Kalven and celsius______
Answer:
[tex]K=C+273.15[/tex]
Explanation:
Kelvin's climbing represents the absolute temperature. Temperature is a measure of the molecular kinetic energy of translation. If the molecules move quickly, with the same energy as in the walls of the container, which makes us feel like "heat". If the molecules do not move, the temperature is zero. 0 K.
The Celsius scale has an artificial zero, defined in the solidification temperature of the water. It is very useful to talk about the weather, and about some simpler technical matters. But it is artificial.
A cylindrical specimen of some metal alloy having an elastic modulus of 117 GPa and an original cross-sectional diameter of 3.6 mm will experience only elastic deformation when a tensile load of 2460 N is applied. Calculate the maximum length of the specimen before deformation if the maximum allowable elongation is 0.47 mm.
Answer:227.56 mm
Explanation:
Given data
Elastic modulus[tex]\left ( E\right )[/tex]= 117 GPa
Diameter[tex]\left ( d\right )[/tex]=3.6mm
force applied[tex]\left ( F\right )[/tex]=2460N
Area of cross-section[tex]\left ( A\right )[/tex]=[tex]\frac{\pi}{4}\times d^{2}[/tex]=10.18[tex]mm^{2}[/tex]
and change in length is given by
[tex]\Delta L[/tex]=[tex]\frac{FL}{AE}[/tex]
[tex]\Delta {0.47\times 10^{-3}}[/tex]=[tex]\frac{2460\times L}{10.180\times 117\times 10^{3}}[/tex]
L=[tex]0.47\times 10^{-3}\times 10.18\times 117\times 10^{3][/tex]
L=227.56 mm
What is the difference between the pressure head at the end of a 150m long pipe of diameter 1m coming from the bottom of a reservoir with a water surface 40m above a receiving reservoir delivering 10m3s-1; and water coming through an identical route in an open rectangular channel of width 1m with the same delivery. Assume that the Darcey Weisbach friction factor is 0.0019 and that the Manning n for the channel is 0.013.
Answer:
[tex]\frac {p_2- p_1}{\rho g} = 31.06 m[/tex]
Explanation:
from bernoulli's theorem we have
[tex]\frac{p_1}{\rho g} + \frac{v_1^{2}}{2g} +z_1 = \frac{p_2}{\rho g} + \frac{v_2^{2}}{2g} +z_2 + h_f[/tex]
we need to find pressure head difference i.e.
[tex]\frac {p_2- p_1}{\rho g} = (z_1 - z_2) - h_f[/tex]
where h_f id head loss
[tex]h_f = \frac{flv^{2}}{D 2g}[/tex]
velocity v =[tex] \frac{1}{n} * R^{2/3} S^{2/3}[/tex]
[tex]S = \frac{\delta h}{L} = \frac{40}{150} = 0.267[/tex]
hydraulic mean radius R =[tex] \frac{A}{P} = \frac{hw}{2h+w} [/tex]
[tex]R = \frac{40*1}{2*40+1} = 0.493 m[/tex]
so velocity is =[tex] \frac{1}{0.013} * 0.493^{2/3} 0.267^{1/2}[/tex]
v = 24.80 m/s
head loss
[tex]h_f = \frac{0.0019*150*24.80^{2}}{1* 2*9.81}[/tex]
[tex]h_f =8.93 m[/tex]
pressure difference is
[tex]\frac {p_2- p_1}{\rho g} = 40 - 8.93 = 31.06 m[/tex]
[tex]\frac {p_2- p_1}{\rho g} = 31.06 m[/tex]
Conduction of electricity is by means of which individual atomic scale species? (Mark all that apply) a)- Quarks b)- Photons c)- Charge carriers d)- Wavicles e)- Klingons
Conduction of electricity is actually just flow of electrons which is a charge carrier. So, answer is "c) Charge carriers"
The current that flows through series elements of a circuit is the same in each element. (a) True (b) False
Answer:
The given statement is true.
Explanation:
In a circuit, in which all circuit elements are connected in series, carries equal or same amount of current through each circuit element as in series circuit current have only one path through which it can flow and the voltage drop across each element depends on the values of resistances or reactances connected in the series circuit and vary depending on their respective respective resistances and reactances whereas the current flowing remain same throughout. Series circuit works on three rules:Current remains same throughout Total resistance equals the sum of individual resistances.Supply voltage equals the sum of voltage drops at each element.The room temperature electrical conductivity of a semiconductor specimen is 2.8 x 10^4 (Ω-m)1. The electron concentration is known to be 2.9x 10^22 m^-3. Given that the electron and hole mobilities are 0.14 and 0.023 m^2/N-s, respectively, calculate the hole concentration (in m^-3)
Given:
[tex]\sigma _{s} = 2.8\times 10^{4} \Omega-m[/tex]
electron concentration, n = [tex]2.9\times 10^{22} m^{-3}[/tex]
[tex]\mu _{h} = 0.14[/tex]
[tex]\mu _{e} = 0.023[/tex]
Solution:
Let holes concentration be 'p'
[tex]\sigma _{s}[/tex] = ne[tex]\mu _{e}[/tex] +pe[tex]\mu _{h}[/tex] (1)
substituting all given values in eqn (1):
[tex]2.8\times 10^{4} = 2.9\times 10^{22}\times 1.6 \times 10^{-19}\times 0.14 + p\times1.6 \times 10^{-19}\times 0.023[/tex]
The cocentration of holes is:
[tex]p = 7.432\times 10^{24} m^{-3}[/tex]
State the two Carnot corollaries (principles)
Answer and Explanation:
The two principles or corollaries of Carnot Theorem are listed below:
1). The efficiencies of all the reversible heat engines between any two thermal reservoirs working between the same temperatures will be equal to each other.
2). For every Carnot engine working between any two thermal reservoirs will have the same efficiency independent of the operating conditions and the nature of working substance. It only depends on the temperature of the thermal energy reservoirs.
What is meant by the critical Reynolds number?
Answer:
Critical Reynolds number is a number or the threshold or the limit at which the laminar flow changes to turbulent flow.
Explanation:
It is basically the ratio of inertial forces to viscous forces and helps to predict if the flow is laminar or turbulent.
from the experiments, for flow in a pipe of diameter D, critical Reynolds number=2300
For Laminar flow: Reynolds number is less than 2000
For transitional flow: Reynolds number is in between 2000-4000, the flow is unstable
For Turbulent flow: Reynolds number is greater than 3500
Reynolds number is different for different geometries
What is "Double Subscript Notation for Stresses"?
Answer:
Stress is a tensor quantity and tensor quantities require 2 sub scripts for their complete definition. 1 subscript defines force and the other area.
Explanation:
Stress at a point is defined as follows
[tex]\sigma =\lim_{\Delta a\rightarrow 0}\frac{\overrightarrow{\Delta F}}{\Delta A}[/tex]
In the expression above in addition to the direction of force F we also need to define orientation of the area that we choose in defining the limit of the quantity on right hand side of the expression above hence we get a dobule subscript notation in stress at a point. 1 subscript defines force and the other area.
Pascal's law tells us that a. force per unit area is constant within a closed container completely filled with a fluid if measured at the same height above a datunm b. force is distributed equally on the walls of a vessel filled with a fluid. c, pressure is transmitted undiminished throughout a closed container d. a. and c e. a. and b
Answer:
d). a and c
Explanation:
According to Pascal's law, when force is applied to a fluid, the pressure will increase equally in all direction of the container. Pascal law says that the pressure is transmitted undiminised in all direction inside a closed container. And the pressure inside the closed container is constant when measured at the same height above the datum.
Hence option d is correct.
One of the following is correct Absolute pressure= Atmospheric pressure - Gauge pressure b)- Gauge pressure=Absolute pressure + Atmospheric pressure c)- Absolute temperature may exist as a negative value d)- The mass in a control mass system constant.
Answer:
(d)
Explanation:
Absolute pressure= Atmospheric pressure+Gauge pressure
hence from this equation we can clearly say that option (A) and (b) is not right.
absolute temperature cannot be negative.
so, option (d) is right.
according to law of mass conservation mass can neither be created nor be destroyed which define control mass i.e. mass in a control mass system is constant
Absolute pressure is calculated by adding the gauge pressure to the atmospheric pressure, represented as Pabs = Pg + Patm. This principle is fundamental in physics, especially for calculations involving fluid dynamics and pressure measurements.
Explanation:The correct relationship between absolute pressure, gauge pressure, and atmospheric pressure is crucial in understanding various phenomena in physics related to fluid dynamics and pressure measurements. Absolute pressure is the total pressure exerted on a system, which includes the atmospheric pressure plus the gauge pressure. Gauge pressure, on the other hand, is the pressure of a system over and above the atmospheric pressure. It is a practical measurement used in most applications because it measures pressure relative to the atmosphere's pressure. In formulas, this relationship is represented as Pabs = Pg + Patm, where Pabs is absolute pressure, Pg is gauge pressure, and Patm is atmospheric pressure.
For example, if a tyre gauge reads 34 psi, this measurement is the gauge pressure. To find the absolute pressure, one must add the atmospheric pressure to this gauge pressure. Considering the atmospheric pressure to be 14.7 psi, the absolute pressure would then be 48.7 psi (which is 34 psi + 14.7 psi). This calculation is fundamental in physics for accurate pressure-related measurements and analyses, especially in applications employing the ideal gas law and other pressure-dependent principles.
Water flows in a pipe of diameter 450 mm at an average velocity of 3 m/s. Determine the volumetric flow rate and the mass flow rate. How long will it take to fill a tank with measurements 5 m x 6 m x 20 m?
Answer:
Volumetric flow rate = 0.4773 m³/s
Mass flow rate = 477.3 kg/s
It will take 286.38 seconds to fill a tank with measurements 5 m x 6 m x 20 m
Explanation:
Given:
Diameter of the pipe through which the water is flowing = 450 mm
Radius = Diameter/2
Thus, Radius of the pipe = 225 mm
The conversion of mm into m is shown below:
1 mm = 10⁻³ m
Radius of the pipe = 225×10⁻³ m
The area of the cross-section = π×r²
So, Area of the pipe = π×/(225×10⁻³)² m² = 0.1591 m²
Also, Given : The water flowing rate = 3 m/s
Volumetric flow rate is defined as the amount of flow of the fluid in 1 sec.
[tex]Volumetric\ flow= \frac {Volume\ passed}{Time taken}[/tex]
This, can be written as Velocity of the fluid from the cross-section area of the pipe.
Q = A×v
Where,
Q is Volumetric flow rate
A is are though which the fluid is flowing
v is the velocity of the fluid
So,
Q = 0.1591 m²×3 m/s = 0.4773 m³/s
Mass flow rate is defined as the mass of the fluid passes per unit time.
[tex]\dot {m}= \frac {Mass\ passed}{Time taken}[/tex]
The formula in terms of density can be written as:
[tex]Density=\frac{Mass}{Volume}[/tex]
So, Mass:
[tex]Mass= Density \times {Volume}[/tex]
Dividing both side by time, we get:
[tex]\dot {m}= Density \times {Q}[/tex]
Where,
[tex]\dot {m}[/tex] is the mass flow rate
Q is Volumetric flow rate
Density of water = 1000 kg/m³
Thus, Mass flow rate:
[tex]\dot {m}= 1000 \times {0.4773} Kgs^{-1}[/tex]
Mass flow rate = 477.3 kg/s
The time taken to fill the volume of measurement 5 m× 6 m× 20 m can be calculated from the formula of volumetric flow rate as:
t= Q×V
So,
Volume of Cuboid = 600 m³
Time = 0.4773 m³/s × 600 m³ = 286.38 s
Water flows through a horizontal plastic pipe with a diameter of 0.15 m at a velocity of 15 cm/s. Determine the pressure drop per meter of pipe (in Pa/m)
Answer:0.1898 Pa/m
Explanation:
Given data
Diameter of Pipe[tex]\left ( D\right )=0.15m[/tex]
Velocity of water in pipe[tex]\left ( V\right )=15cm/s[/tex]
We know viscosity of water is[tex]\left (\mu\right )=8.90\times10^{-4}pa-s[/tex]
Pressure drop is given by hagen poiseuille equation
[tex]\Delta P=\frac{128\mu \L Q}{\pi D^4}[/tex]
We have asked pressure Drop per unit length i.e.
[tex]\frac{\Delta P}{L} =\frac{128\mu \ Q}{\pi D^4}[/tex]
Substituting Values
[tex]\frac{\Delta P}{L}=\frac{128\times8.90\times10^{-4}\times\pi \times\left ( 0.15^{3}\right )}{\pi\times 4 \times\left ( 0.15^{2}\right )}[/tex]
[tex]\frac{\Delta P}{L}[/tex]=0.1898 Pa/m
Which of the following is not an oxidizer? a)- H2O2 b)- CH c)- N2O4 d)- LO2
Answer:
Out of the given options
option (b) CH
is correct.
Explanation:
'CH' is not an oxidizer, it is a reducing agent.
Oxidizer or oxidizing agents are those substances that undergo chemical reactions in order to accept one or more electrons from atoms of other substances and are able to oxidize these substances. Oxidizers are electron acceptor species and are themselves reduced. Some of the examples of Oxidizers are oxygen,halogens, etc.
What is the approximate theoretical maximum efficiency of a heat engine receiving heat at 627°C and rejecting heat to 27°c? a)-23.2 b)-0.96 c)-0.04 d)-0.33 e)-0.66
Answer:
The correct option is (e) η = 0.66
Explanation:
given data:
temperature at entry is 627 degree C
temperature at exit is 27 degree C
the efficiency of a engine is given as η
[tex]\eta = (1-\frac{T_{L}}{T_{H}})*100[/tex]
where [tex]T_{L}[/tex] is temperature in kelvin at exit point
[tex]T_{H}[/tex] is temperature in kelvin at entry point
[tex]\eta = (1-\frac{27+273}{627+273})*100[/tex]
η = 66.66 %
Nickel superalloys are selected for high-temperature gas turbine blades because of: a)High modulus. b)High creep strength. c)High maximum working temperature. d) b and c.
Answer:
The correct option is : d) b and c.
Explanation:
A superalloy, also known as a high performance alloy, is a class of alloys that shows the following characteristics: high mechanical strength, surface stability, resistance to thermal creep and resistance to oxidation or corrosion at high temperatures.
Therefore, a nickel base superalloy is commonly used for the high temperature gas turbine blades because of high thermal creep strength and high maximum working temperature due to its stability at high temperatures.