Final Exam Flashcards
(50 cards)
AC can be converted into DC by passing the AC through a ______.
Rectifier (diode)
AC electricity was chosen as the preferred form of electrical power from the power plant because its ______ can easily and efficiently be changed using a ______
Voltage (and current),
Transformer
*Easy to change AC to DC (but difficult & costly to change DC to AC)
AC power of 100 volts and 1 ampere enters a transformer with 5 coils and exits the transformer with 25 coils. What is the exiting voltage and current?
V in x N out / N in = V out
100 x 25 / 5 = 500 volts
Amps in x N in / N out = current
1 x 5/25 = 0.2 amps
Albert Einstein won a Nobel Prize in 1922 for telling us about the photoelectric effect. Which
one of Burkes major technologies owes its origin to the photoelectric effect?
Television
Antimatter was first observed in 1955. Since then extremely small amounts have been made. When antimatter contacts matter the matter changes into ______.
Energy
Burke believes that ordinary people are often prevented from sharing in scientific and technological discussions because they:
lack jargon (specialized words)
Daniel Bernoulli told us about the physics of fluids and described it mathematically telling us that [density x velocity2/2) + pressure = constant] which means fluid velocity is inversely related to its pressure. A flying Frisbee floats partly because the velocity of air passing over the frisbee’s _____ is _____ than the air velocity passing the bottom therefore creating higher pressure on the frisbee’s bottom creating lift
Top,
Higher
Early 20th century, American scientist, inventor and educator responsible for increasing the farmers’ productivity and wealth.
George Washington Carver
Eight great technologies according to Burke:
1) Nuclear Power
2) Telecommunications
3) Computer
4) Assembly line
5) Jet engine/Air Transport
6) Plastics/Synthetic Polymers
7) Liquid fuel rockets
8) Television
Einstein also told us E=mc2which tells us that the_____ and ______ of an object is directly proportional and interchangeable.
Mass; Energy
Electrical power loss in the transmission cable is equal to resistance x current2. This electrical power is sent at very high voltage to _____. (Hint: remember power = current x volts)
Reduce Current
Give a unit of electrical power equivalent to J/s.
Watts (W)
Give examples of genetically modified items you may have used recently.
Tomotoes
Graphite, diamonds, and buckminsterfullerene are all allotropes of ____
Carbon
How are communications and technological development related?
Rate of technology change is proportional to rate of information exchange (communication)
How does a light emitting diode, LED, works?
Electrons from the higher energy N side drop at the junction to lower energy p side. Giving off the energy as light particles (photons).
Identify at least 3 modern technologies dependant on glass
- tv
- electronics,
- insulation
- reinforcement
- adiabatic containers
If the power running through a power line is 20,000 watts and the voltage is 1000 volts then
what is the current in the line?
Current = power / voltage
Current = 20,000 / 1000 = 20 amps
If we could convert 2 grams of matter into energy it would be equivalent to about ___ Hiroshima size atomic bombs.
3
In a diode electrons flow in one direction, from the _____ to the ________.
Cathode; Anode
In a special type of solid-state diode the N side is higher energy than the P side and under forward bias current flow electrons combine with holes at the junction interface to produce ____.
light particles (photons)
In electromagnetic induction a spinning magnet (fluctuating magnetic field) induces _______ into conductive coils, which surround the magnet.
Electricity
In fluid flow, how are pressure and velocity related?
inversely proportional
In the garden hose analogy to electricity the _____ is analogous to resistance (ohms) and the ______ is analogous to volts.
hose;
water pressure
