Magnetic flux lines, by itself, is not very useful. You can’t see them. You can’t touch them. They can’t be detected by sensors. So, by themselves, they are not very useful. Yet, as a concept they very useful. But within a context, when they are changing in time, in the vicinity of other things (what things?) they are important. Explain where Magnetic Flux is useful, where it is important?

A 4.0-cm-diameter parallel-plate capacitor with a 1.0 mm spacing is charged to 1000 V. A switch closes at t =0s, and the capacitor is discharged through a wire with 0.20? resistance.

Part A

Find an expression for the magnetic field strength inside the capacitor at r =1.0cm as a function of time t (where t is in ps).

Part B

Draw a graph of B versus t.

Singly ionized (one electron removed) atoms are accelerated and then passed through a velocity selector consisting of perpendicular electric and magnetic fields. The electric field is 160 V/m and the magnetic field is 3.18×10^?2 T . The ions next enter a uniform magnetic field of magnitude 1.73×10^?2 T that is oriented perpendicular to their velocity.

(A) If the radius of the path of the ions in the second magnetic field is 17.1 cm , what is their mass?

Consider a beam of light passing from air into glass (refractive index 1.5) at an angle of 30 degrees from vertical. Calculate

- The angle of the reflected light

- The angle of the refracted light

- The intensity of the reflected light

- The intensity of the refracted light

Why can you electroplate using metals like copper or silver but not materials like carbon or oxygen? (Hint: Look up the difference between metals and non-metals.)

Two vehicles are approaching an intersection. One is a 2300 kg pickup traveling at 13.0 m/s from east to west (the ?x- direction), and the other is a 1300 kg sedan going from south to north (the +y?direction at 21.0 m/s ).

Q1: Find the x -component of the net momentum of this system.

Q2: Find the y-component of the net momentum of this system.

Q3: What is the magnitude of the net momentum?

Q4: What is the direction of the net momentum?

Four traveling waves are described by the following equations, where all quantities are measured in SI units and y represents the displacement.

Which of these waves have the same speed?

      I:    y = 0.12 cos(3x - 24t)

      II:  y = 0.15 sin(6x + 32t)

      III: y = 0.13 cos(6x + 24)

      IV: y = -0.27 sin(3x - 42t)

Q3a.

Define the specific heat capacity, and state its units.

b.

A Cu bar, 0.5 m long and 1 cm in thickness, is placed in a stream of boiling water at one end, and in a 2 kg block of ice at -10°C the other end. The thermal conductivity of Cu is 380 Wm-1K-1, the specific heat capacity of ice is 210 Jkg-1K-1 and the latent heat of melting of ice is 0.34 x106 Jkg-1. How long will it take to completely melt the ice block?

c.

Using the Thermal Shock Resistance equation explain what mechanical and physical properties would contribute to increased thermal shock resistance, and why silica is good at resisting thermal shock.

d.

Define convection.

e.

State the equation for the Rayleigh Number, defining all of the terms.

1(a)
Draw a schematic representing a dislocation, in 2D.
(b)
Describe what is meant by work-hardening? Explain with an example.
(c)
Assume you are stretching a bar of metal that undergoes work hardening. What would the Stress vs Strain diagram of such a material look like, showing deformation behaviour?
(d)
Define the Following:
(i) What is a Fracture?
(ii) Define the types of Fracture.
(iii) Draw the types of Fractures.
(iv) What is Fracture Toughness?
(v) What are Stress Concentrators?

(e)

State at least two situations in which the possibility of failure is part of the design of the component or Product.

1.(a)
Define what are Crystalline Solids and Amorphous Solids?
(b)
Explain, with a two-dimensional representation, the amorphous and crystalline forms of SiO2?
(c)
The density of matter largely depends on the atomic weight of the atoms and how closely packed they are in the crystal structure. The atomic weight of nickel is 58.70 amu, and it has a face-centred cubic structure, with a lattice parameter of 3.52 Å. Estimate the theoretical density of nickel.

When do we use I=P/a or I=P/4pi(r)^2?

for example question 1:

30 seconds of exposure to 115 dB sound can damage your hearing, but a much quieter 94 dB may begin to cause damage after 1 hour of continuous exposure.You are going to an outdoor concert, and you'll be standing near a speaker that emits 50W of acoustic power as a spherical wave. What minimum distance should you be from the speaker to keep the sound intensity level below 94 dB?

- we used I=P/4pir^2

Question 2:

A woman wearing an in-ear hearing aid listens to a television set at a normal volume of approximately 60 dB. To hear it, she requires an amplification of 30 dB, so the hearing aid supplies sound at 90 dB to the ear canal, which we assume to be circular with a diameter of 7 mm. What is the output power of the hearing aid?

why did we use I=P/a not I=P/4pir^2?

A kettle is filled with tap water and placed on a stove. The stove element is turned on. Explain why the water starts to boil after a while.

Derive the Maxwell construction by considerations involving the minimization of the Gibbs potential instead of the Helmholtz free energy.

Please help me...

12. How is constructed the deformation tensor?

Start with an ideal gas of volume 4m^3, at a pressure of 1200Pa, and temperature 289K. Construct a cycle using 3 or more processes (of your choice). For each process in your cycle calculate the Q, ?U, and W. Calculate the net change in each of these quantities for the entire cycle, and determine whether the work as a result of the cycle is done ON or BY the system.