Nano Midterm 1
Give the electronic configuration of Silver.
[Ag] 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d1
Based on the scaling laws, how many times greater is the strength- to-weight ratio of a nanotube (D=10 nm) than the leg of a flea (D =100μm)?Than the leg of an elephant (D=2 m)?
2E8:20000:1
Following the question 5, estimate the temperature of the Sun in K.
5796 K
in question 18, approximately how much energy is needed to heat a hot tub with D=2 m?
6.24x10^8
Use atoms to explain how a larger container leads to a lower pressure.
The pressure is the individual gas molecules colliding over and over again with the container walls, exerting a force per unit area. If you make the volume of a container larger, the molecules' collisions with the wall will occur less frequently. This means that the pressure will decrease.
What are the three main components of an atom?
protons, neutrons, and electrons
what is the resistance of a cubic micrometer of copper (resistivity=17.2 x 10-9 ohmsxmeter)
0.017
Which of the following lists of sublevels are given in ascending energy level?
2p, 3s, 3p, 4s
in question 14, if the mirror's dimensions can be reduced to 1/3 of original size, what is the corresponding percent reduction in the torque required to turn the mirror?
0.6%
True or false: Miniaturization improves the factor of safety of a product.
False
A stoplight radiates visible green light that has a wavelength of about 545 nm. What is the frequency of this light?
5.5 x 10^14
find a value of x that the probability of nding the electron is the highest.
50 pm
If 4.45 × 10−8% of the Sun's photons reach Earth, estimate the average intensity of this radiation on the Earth's surface in W/m2 (radius of the Earth: 6.37 × 106 m).
1305 W/m^2
The calorie is a unit of energy defined as the amount of energy needed to raise 1 g of water by 1°C. How many calories are required to bring a pot of water at 1°C to a boil? The pot is full to the brim, with diameter 20 cm and depth 20 cm. The density of water is 1000 kg/m3.
623700 calories
Sun generates an average 3.74 × 1026 W of power. Assume the wavelength of the Sun's radiation is 500 nm. Approximately how many photons the Sun emits every second.
9 x 10^44
The distance between the nuclei of two iron atoms is about 4 Angstroms (1 Angstrom=10-10m). (a) How many nanometers is that? (b) How many iron atoms on this spacing would it take to reach 2 microns (1 micron=10-6m)?
A) 0.4 nm; B) 5,000 atoms
Calculate the mass of an atom of (a) hydrogen (1.0 g/mol); (b) silver (107.87 g/mol); (c) silicon (28.09 g/mol).
A) 1.66x10^-24 B)1.79x10^-22 C)4.66x10^-23
Data from the 2004 Olympic Games in Athens, Greece are provided in Table 2.2. Plot the percentage of body weight lifted versus weight class. Is the same trend evident in the women's weightlifting event as the men's event shown in Figure 2.4? In what weight class is there a discrepancy and how might this be explained?
Convert lbs to kg, then divide lift weight by weight class.
If energy costs 10 cents per kilowatt-hour, how does the price (in dollars) of heating the hot tub scale with the tub's characteristic dimension?
Cost ∝ 0.1X D^3
Rank the following things from largest to smallest: polio virus, drop of water, mercury atom, e coli bacterium, helium atom, human red blood cell.
Drop of water, human red blood cell, e coli bacterium, polio virus, mercury atom, helium atom
Iyy= rhtw^3 / 12. choose the right scaling law
Iyy= L^5
The number 1,234,567 written out is one million, two hundred thirty four thousand, five hundred sixty seven. Write out this number: 1,200,300,400,500,600,700,800,901
One septillion, two hundred sextillion, three hundred quintillion, four hundred quadrillion, five hundred trillion, six hundred billion, seven hundred million, eight hundred thousand, nine hundred and one
Look up the number of valence electrons for the following atoms: a. Silicon b. Beryllium c. Oxygen d. Argon
a) 4; b) 2; c) 6; d) 8
Look up the number of valence electrons for the following atoms a. Silicon b. Beryllium c. Oxygen d. Argon
a=4; b=2; c=6; d=8
Scaling laws derive from: (a) design engineers' experience, (b) market demands, (c) the laws of physics, (d) the material used.
design engineers' experience
in designing an electrostatic actuator made from parallel plates, which one of the following is the best option to improve the electrostatic force
halve the distance separating the plates
According to the Heisenberg uncertainty principle, the more precisely you know the position of an electron, what is known less precisely?
momentum
Give at least four advantages of miniaturization in machine design.
multi functionality, improved strength to weight ratio
