Question

Mechanics

23What is the drift speed of the conduction electrons in a copper wire with radius r =900 mm when it has a uniform current / = 17mA? Assume that each copper atom contributes one conduction electron to the current and that the current density is uniform across the wire's cross section. The number of electrons per unit volume, n =8.49 x 1028 m-3

\text { d. } 6.0 \times 10^{-9} \mathrm{~m} / \mathrm{s}

\text { b. } 5.0 \times 10^{-6} \mathrm{~m} / \mathrm{s}

\text { c. } 4.9 \times 10^{-7} \mathrm{~m} / \mathrm{s}

\text { a. } 3.0 \times 10^{-7} \mathrm{~m} / \mathrm{s}

\text { e. } 3.5 \times 10^{-8} \mathrm{~m} / \mathrm{s}

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### Question 45701

Mechanics

Q3 [45%] Consider the probability of finding a molecule in its ground state, P(e0),or first excited state, P(ɛ1), given the that energy separation between the two statesis 5 kJ/mol. You may assume that the states are non-degenerate (go = g1 = 1).
3] Calculate BAE for this system at 300 K.
[15%] Calculate the ratio of the excited and ground state populations P(ɛ1)/P(ɛo) at temperature T = 300 K
3. [15%] Show (by calculation) what would happen to the ratio if the temperature was increased by a factor of two.

### Question 45700

Mechanics

Q2 [30%] Electron kinetic energies are often measured in units of electron-volts(1 eV = 1.6 x 10-19 J). When an aluminum plate is irradiated with UV light of 200nm wavelength, the ejected electrons are observed to have an average kinetic energy of about 2.11 eV. Use these results to
] Calculate the photon energy (in eV units).
Determine the electron binding energy O of aluminum (in eV units).

### Question 45699

Mechanics

Q1 [25%] Consider a ball with mass m=5.0 kg on a hill with height h=10 m whichis inclined at an angle 0=30 degrees with respect to the horizontal axis and recallthat g=9.8 m/s².
] Calculate potential energy due to gravity11 1
Calculate the force on the ball due to gravity
Calculate the component of the force along the slope (z-axis).

### Question 45661

Mechanics

What is the maximum mass of this water strider so that it can keep from breaking through the water surface? The strider has six legs

### Question 45660

Mechanics

What is the maximum possible upward force on the foot due to surface tension of the water?

### Question 45659

Mechanics

Blood plasma (at 37.0°C) is to be supplied to a patient at the rate of 2.80 × 10-6 m³/s. If the tube connecting the plasma to the patient's vein has a radius of 2.00 mm and a length of 60.8 cm, what's the pressure difference between the plasma and the patient's vein? Viscosity1.30 x 103 Pa·s.blood plasma is
39.55 Pa

### Question 45658

Mechanics

Four identical sections of pipe are connected in various ways to pumps that supply water at the pressures indicated in the figure. The water exits at the right at 1.00 atm. Assume viscous flow. If the total volume flow rate in system Bis 0.0128 m³/s, what is the total volume flow rate in systemC?

### Question 45657

Mechanics

Estimate the air speed above the wings. Density of air is 1.29 kg/m3.

### Question 45656

Mechanics

An airplane flies on a level path. There is a pressure difference of 524 Pa between the lower and uppersurfaces of the wings. The area of each wing surface is about 100 m². The air moves below the wings ata speed of 80.5 m/s.
Estimate the weight of the plane.

### Question 45655

Mechanics

The average speed of blood in the aorta is 0.320 m/s, and the radius of the aorta is 1.00 cm. There are about 2.00 × 10° capillaries with an average radius of 6.49 µm. What is the approximate average speed of the blood flow in the capillaries?