..................................................
Answer:
a) 75%
b) 82%
Explanation:
Assumptions:
Properties: The density of water
Conversions:
Analysis:
Note that the bottom of the lake is the reference level. The potential energy of water at the surface becomes gh. Consider that kinetic energy of water at the lake surface & the turbine exit is negligible and the pressure at both locations is the atmospheric pressure and change in the mechanical energy of water between lake surface & turbine exit are:
Then;
gh = 0.491 kJ/kg
= 1559 kW
Therefore; the overall efficiency is:
= 0.75
= 75%
b) mechanical efficiency of the turbine:
thus;
![\eta_{turbine} = \dfrac{\eta_{[turbine- generator]} }{\eta_{generator}} \\ \\ \eta_{turbine} = \dfrac{0.75}{0.92} \\ \\ \eta_{turbine} = 0.82 \\ \\ \eta_{turbine} = 82\%](https://tex.z-dn.net/?f=%5Ceta_%7Bturbine%7D%20%3D%20%5Cdfrac%7B%5Ceta_%7B%5Bturbine-%20generator%5D%7D%20%7D%7B%5Ceta_%7Bgenerator%7D%7D%20%5C%5C%20%5C%5C%20%5Ceta_%7Bturbine%7D%20%3D%20%5Cdfrac%7B0.75%7D%7B0.92%7D%20%5C%5C%20%5C%5C%20%5Ceta_%7Bturbine%7D%20%3D%200.82%20%5C%5C%20%5C%5C%20%5Ceta_%7Bturbine%7D%20%3D%2082%5C%25)
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 =
so, a = 
m = mass of each atom in a unit cell
mass of an atom =
,
where,
is Avagadro Number = 6.02×10^{23}
volume of unit cell = a^{3}
density, ρ = 
density, ρ = 
ρ = 
ρ = 10.215gm/
Answer:
D. Brake
Explanation:
NJMVC is an acronym for New Jersey Motor Vehicle Commission and it is an agency of government that was established in 2003. NJMVC is saddled with the responsibility of inspecting, titling of number plates and registration of motor vehicles, as well as licensing of drivers in New Jersey, United States of America.
The NJMVC subject the applicants (drivers) to a series of test before they are issued a valid driver's license, some of these tests include;
1. Vision test.
2. Knowledge test.
3. Road test.
All of the above mentioned tests must be passed by a driver before he or she are issued a valid driver's license.
Some of the test drive requirements are;
- Valid registration documents.
- Valid sticker of inspection.
- No obstacle or center consoles should prevent the examiner from accessing both the foot brake and parking brake.
Hence, NJMVC will reject a vehicle from the road test if the examiner does not have access to a brake. Thus, the brakes are required to be in good working condition prior to the road test.
However, if an applicant (driver) passes the road test he or she would be issued an authorization for licensing by the examiner and then a digital driver's license by the motor vehicle commission.