Week 4 Day 2

Question 1

hydrostatics

Answer 1

study of stationary fluid

w = m * g = p * V * g = P * A * h * g

P = W / A

Question 2

Pascal’s principle

Answer 2

when an external pressure is applied to a confined fluid, it is transmitted unchanged to every point within that fluid.

P₁ = P₂

F₁ = F₂ * (A₁/A₂)

Question 3

hydrodynamics

Answer 3

study of moving fluid

Flow = volume/time (m³ /sec)

If flow is constant:

velocity = flow / area

*fluid in a smaller tube will go faster, assuming same flow rate

Question 4

Bernoulli Equation

Answer 4

An increase in the speed of a fluid occurs simultaneously with a decrease in pressure or in the fluid’s potential energy

P₁-P₂ = ½d * v₁² *((A₁/A₂)² -1)

Question 5

Flow

Answer 5

Flow = A₁ * V₁ = A₂ * V₂

Question 6

Venturi effect

Answer 6

the reduction of fluid pressure when fluid flows through a constricted section of a pipe.

Question 7

viscosity

Answer 7

describes the fluids resistance to flow.

(mPa)

Question 8

Poiseuille’s equation

Answer 8

Gives the pressure drop in a flow across a length of tube

Flow = (P₁-P₂) * π * r⁴ / (8 * n * L)

n = viscosity

L = length

Question 9

charge on an electron

Answer 9

1.602 x 10^-19 C

1 C = 6.24 x 10¹⁸ e

Question 10

Coulomb

Answer 10

SI unit of electrical charge

1 C = 6.24 x 10¹⁸ electrons

one Ampere second

1 Volt / Amp

Question 11

Coulomb’s Law

Answer 11

F = k * q₁ *q₂/r²

k = 8.99 x 10⁹ N*m²/C²

F can be + (repulsive) or - (attractive)- opposites attract

Question 12

electric potential energy

Answer 12

Joule (kg * m²/s²)/ Coulomb

or

Volt

potential energy of two charges repulsing each other. If one is unable to move, the other charge will be repulsed by first charge, giving it potential energy

Question 13

volt

Answer 13

1 Joule/Coulomb

SI unit for electric potential energy

Question 14

electric current

Answer 14

1 Amp = 1 Coulomb / second

flow of electric charge, measured in charge/time

Question 15

conductors

Answer 15

carry electrical current efficiently

*metals are generally good conductors

Question 16

insulators

Answer 16

resist carrying electrical current

most non metals

Question 17

Ohm’s law

Answer 17

the voltage driving electrons through a circuit is directly proportional to the volume of electron flow and the resistance of the medium to that flow.

V = IR

I = current (amps)

V= voltage (volts)

R = resistance (ohms)

Question 18

Answer 18

symbol for resistor

Question 19

Question 20

Answer 20

Single pull, single throw

ex. light switch

Question 21

Answer 21

resistors in series

R_total = R₁ + R₂ + R₃…R_n

Question 22

Answer 22

resistors in paralles

G_total = 1/R₁ + 1/R₂ + 1/R₃….

Question 23

electrical power

Answer 23

power is current times voltage

P (W) = I * V

I= current (amp)

V = voltage (volt)

W = watt

OR J/sec = C/sec * J/C

Question 24

Electrical Energy

Answer 24

Energy (J) = power (J/s) * time (s)

expressed as kilowatt-hour

1 kWh = 1000 W * hr

Question 25

Semiconductors

Answer 25

properties of both conductors and non conductors

silicon and germanium

Question 26

p-type semiconductor

Answer 26

Group IV doped with Group III

leaves a positive hole in structure

Question 27

n-type semiconductors

Answer 27

Group IV doped with froup V

leaves a negative hole in structure

Question 28

diode

Answer 28

a p-type semiconductor bound to an n-type semiconductor

*A diode will conduct electricity in one direction, not the other

Question 29

transistors

Answer 29

use semiconductors to control the current that goes through

(E –> B) current controls current between (E –> C)

(E –> C) current is greater than (E –> B), so it can be used as amplifier

Question 30

spectroscopy

Answer 30

shining light through, or reflecting light off a material; wavelengths of light that are absorbed by the material will not be transmitted or reflected

Question 31

Beers law

Answer 31

Absorbance (A) for a wavelength of light depens on the absorbtivity (a) of the material, the concentration (c) and the thickness (b)

A = a * b * c

Question 32

Alpha decay

Answer 32

loses an ₂⁴He.

All elements with atomic numbers greater an 83 experience Alpha decay.

Question 33

Beta- decay

Answer 33

Neutron turns to proton and kicks out an electron an antineutrino

Question 34

Beta + decay

Answer 34

proton turns to neutron and kicks out a positron

*used for PET scans

Question 35

half life

Answer 35

time it takes for half a radioactive material to decay

N(t) = N(0) * e^{-(decay constant * t)}

Question 36

Planck’s constant

Answer 36

E = h * c/(wavelength) = h * f

f = frequency

c = speed of light

Question 37

decay rate

Answer 37

number of radioactive decays or disintegrations occurring per unit time

SI unit becquerel (bq)

1 Bq = 1 disintegration/sec

Curie (Ci)

1Ci = 3.7 x 10¹⁰ Bq