(a) What is quantum tunneling?

(b) Based on the concept of quantum tunneling, describe the working principle of a scanning tunneling microscope.

(c) Explain what is quantum confinement?

(d) You have a metallic nanowire. The length of the nanowire is 1 mm (Comparing with the wave length of electrons, you can think the length is infinitely long.) The width of the nanowire is 50 nm. The height of the nanowire is 20 nm. Based on the simple model we discussed in our lecture, write out the formula of the energy of electrons in the nanowire (formula is enough, no calculation is required).

Cut the copper cubes to a volume of 0.5 cm^3. If the copper has a density of 8.96 g / cm^3
1 If 1 copper atom has 1 Conduction electron, calculate the total number of Conduction electrons in the copper cube.
2 At room temperature, the conduction electrons in the copper cube behave as Ideal gas or Degenerate gas. Why?
3 Explain the meaning of Fermi energy and Fermi temperature.
4 At zero Kelvin temperature, what energy can the Conduction electrons in the copper cube be? And find the total power of the Conduction electrons
5 How are Conduction electrons different from item 3.4?

If the net force on an object is zero then
Group of answer choices

the object's speed can change.

the object must be at rest.

the object's speed is constant but its direction might be changing.

the object has zero acceleration.

A parallel-plate air capacitor of area A=12.0cm² and plate separation d=3.80mm is charged by a battery to a voltage 66.0V. If a dielectric material with kappa=3.60 is inserted so that it fills the volume between the plates (with the capacitor still connected to the battery), how much additional charge will flow from the battery onto the positive plate?

When two unknown resistors are connected in series with a battery, the battery delivers 230 W and carries a total current of 5.00 A. For the same total current, 55.0 W is delivered when the resistors are connected in parallel. Determine the values of the two resistors.

A) Electrons accelerated by a potential difference of 13.16 V pass through a gas of hydrogen atoms at room temperature. Calculate the wavelength of light emitted with the longest possible wavelength.

B) Calculate the wavelength of light emitted with the shortest possible wavelength.

d. Draw a diagram that illustrates how nuclei change during nuclear fusion. Write 2 - 3 sentences describing the process of nuclear fusion, including where it occurs and how the energy released can be harnessed for use in homes. (8 points)

A boy standing on the ground close to a building throws a ball vertically upward. From his measurements of the maximum height, y-max, to which the ball rises and the time required to reach this height, the boy calculates that the average velocity of the ball on its way up is 20 m/s. Five seconds after leaving the boys hand, the ball is caught by a girl who has stretched her arm out of a window some distance above the boy. You may use -9.8 m/s^2 for the value of g.

a. What is the velocity of the ball immediately after its release?

b. How high does the ball rise; i.e., what is the value of y-max?

c. At what height, y, above the point of release is the ball caught?

d. What is the velocity of the ball immediately before being caught

Colby participates in a rocket-launch competition in her high school. The goal is to launch a rocket with mass m = 2.3 kg [5 lbs] to a height no less than 50-m (164 ft) above ground.

a) What is the minimum momentum of the rocket as it leaves the launch pad?

b) Colby figured out three possible propulsion mechanisms that differ by the generated force F (“thrust”) and the time interval ∆t during which the force acts on the rocket [“burn time”]: Force F [N] Time interval ∆t [s] Propulsion #1 161 0.41 Propulsion #2 233 0.37 Propulsion #3 532 0.12 What is Colby’s best choice for the propulsion mechanism? Explain your reasoning!

c) Colby is excited about the successful launch of her rocket but is disappointed because the rocket is in air for only t1 = 3.1 s after the launch until it reaches the highest point. Explain Colby’s disappointment and calculate the air resistance acting on the rocket! Assume that the air resistance is constant.

d) Does Colby’s rocket meet the requirement of the contest?

e) The rocket returns to the ground at the time t2 = 6.5 s measured from the time of the launch. Calculate the impulse imparted on the rocket during the flight form the highest back to the ground. Find the velocity vector!] of the rocket just before it lands on the ground!

A bead slides down along a piece of wire that is in the shape of a helix. The helix lies on the surface of a vertical cylinder of radius r, and the vertical distance between turns is d. (a) Ordinarily when an object slides downhill under the influence of kinetic friction, the velocity-independence of kinetic friction implies that the acceleration is constant, and therefore there is no limit to the object’s velocity. Explain the physical reason why this argument fails here, so that the bead will in fact have some limiting velocity. (b) Find the limiting velocity. (c) Show that your result has the correct behavior in the limit of r → ∞.

A 1.5 kg ball is thrown vertically upward with an initial speed of 15 m/s. If the initial potential energy is taken as zero, find the ball’s kinetic, potential, and mechanical energies (a) at its initial position, (b) at 5 m above the initial position, and (c) at its maximum height.

Could a fuel cell which combines H2 and O2 to form H2O and produce electricity directly be more efficient than a Carnot heat engine attached to an electric generator? Explain.

1.The Vector Product or otherwise know Cross Product of two vectors is itself another vector. When is the product zero?

2.How does one find the resultant vector of multiple vectors added together?

3.The change in displacement divided by the time interval over which the change in displacement occurs is known as what?

4.The change in velocity divided by the time interval in which the change in velocity occurs is known as what?

5.The constant acceleration of a freely falling object is called the ______?

6. In “Ideal” Projectile motion (No air resistance) how does the velocity in the horizontal direction behave throughout the flight of an object? And what is the flight path known as?

7.Acceleration of an object in uniform Circular motion is radial, what does this mean? And what is it sometimes called?

1.What is the First Condition of Equilibrium?

2.Explain what Pythagorean Theorem is and give the formula. ?

3.The Scalar Product or otherwise known Dot Product of two vectors is the sum of the products of their respective components. What does the scalar product give us? And when is the product zero?