MIDTERM EXAM
ECE1354
Spring 2023
Name:
1. What is the relationship between power and energy? Energy and Power have the following
relationship: An amount of energy is a joule. A watt is a power unit that measures the rate of
change of energy.
2. What are the three particles (or types) of energy that ECEs work with? Fundamental particles
like electrons, protons, and neutrons make up atoms.
3. How do we create an electromagnetic (EM) field? Our energy always radiates as an
electromagnetic field from a moving charge or current.
4. What form of energy is most commonly wasted in ECE applications? The biggest energy
waster and a significant barrier to many popular technologies is thermal energy.
5. What is the unit that we use to measure current, and what does that unit mean (what does
current mean is physically happened)? Current (I), which is measured in amps (A), is the
amount of charge that moves through a cross-sectional area in a certain amount of time (current
= charge/second).
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6. What is the difference between resistance and resistivity? A substance's ability to physically
resist the flow of current is known as resistance. However, resistivity is a physical characteristic
of a specific substance with certain dimensions.
7. What is the difference between resistance and impedance? Voltage divided by resistance in a
resistor equals resistance. Voltage divided by current for any component is referred to as
impedance.
8. The current (I) passing through a capacitor (C) is given by I = C × dV/dt, where dV/dt is how
quickly the voltage (V) is changing in time. For a DC voltage that has no frequency, does the
capacitor look like an open circuit (a broken wire with no current) or a short circuit (an unbroken
wire with lots of current)? Pick one. The capacitor looks like an open circuit because if was short
there would be a current that flows I = Veq/Req.
9. Let's say we have a block of metal. What are two things we could do to that block to change
its electrical resistance? Please indicate if each change would make the resistance go up or
down. The resistance will reduce slightly if the cross sectional area of the central portion of your
conductor is increased. The energy rises together with the frequency.
10. Below are the current-voltage relationships of two objects. Which follows Ohm's Law? It may
be none, one, or both. Example B demonstrates Ohm’s Law.
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11. When in parallel, does the smaller or larger resistance dominate the circuit? When in series,
does the smaller or larger resistance dominate the circuit? Dominate means to control what the
overall resistance of the circuit is ... does the overall resistance look like the larger or smaller
resistance?
Parallel
Smaller
Dominant Resistance
(“Smaller” or “Larger”)
Series
larger
12. In the below circuit, are any two resistors in parallel or in series? If so, which ones? No need
to assume any combining of resistors, you can just evaluate the circuit as is. R5 and R4
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13. In the below circuit, what is the value of the current (I) and the voltage (V)? Hint, you can
answer this question with one use of Kirchoff’s Current Law and one use of Kirchoff’s Voltage
Law! 1A= 0.5A+2V
14. The sensor that measure the battery life on your mobile phone, does that produce an analog
signal or a digital signal? Why? Our phones' battery life sensors are digital since they can encode
data using different bases (such binary 1's or O's).
15. Name one technology that you feel will greatly impact society over the next ten years. Why
do you think this is so? Artificial intelligence is one technology that you believe will have a
significant impact on society over the next ten years. Well, some will claim that it has already
transformed the world, but I believe there is still much more to come. Artificial intelligence's
potential to increase employee productivity will impact individuals simply empowering them to
achieve greater results. The human workforce is released to concentrate on activities for those
for which they're more qualified, such as those requiring creativity and sensibility, while the future
of AI replaces laborious or risky activities.
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