Electricity Flashcards
(139 cards)
1
Q
Flashcard 1:
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2
Q
front: What is the formula to calculate potential difference across two points in a circuit?
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3
Q
back: Potential difference (V) = Work done (W) / Charge (Q)
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4
Q
Flashcard 2:
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5
Q
front: How is electric current defined in terms of charge and time?
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6
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back: Current (I) = Charge (Q) / Time (t)
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7
Q
Flashcard 3:
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8
Q
front: State Ohm’s Law in terms of voltage
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current
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Q
back: Voltage (V) = Current (I) × Resistance (R)
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10
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Flashcard 4:
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11
Q
front: What does Ohm’s Law explain about the relationship between voltage and current?
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12
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back: Ohm’s Law states that the potential difference (voltage) across a conductor is directly proportional to the current through it
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at a constant temperature.
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Q
Flashcard 5:
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14
Q
front: What is the unit of work or energy in the SI system?
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15
Q
back: Joule (J)
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16
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Flashcard 6:
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17
Q
front: What is the SI unit of electrical power?
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18
Q
back: Watt (W)
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19
Q
Flashcard 7:
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20
Q
front: What unit is used to measure electrical charge?
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21
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back: Coulomb (C)
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22
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Flashcard 8:
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23
Q
front: What is the SI unit for electrical resistance?
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24
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back: Ohm (Ω)
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Flashcard 9:
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front: What unit measures electric current?
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back: Ampere (A)
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Flashcard 10:
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front: What is the SI unit for potential difference (voltage)?
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back: Volt (V)
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Flashcard 11:
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front: What kind of relationship is described by "directly proportional"?
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back: If one variable increases
the other variable increases as well
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Flashcard 12:
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front: In a graph showing Ohm’s Law with voltage on the y-axis and current on the x-axis
what shape does the graph take?
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back: A straight line through the origin.
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Flashcard 13:
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front: How is the resistance calculated from the graph of voltage versus current?
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back: Resistance = Gradient = Change in Voltage / Change in Current
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Flashcard 14:
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front: What kind of conductor produces a straight line graph of voltage versus current through the origin?
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back: An ohmic conductor.
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Flashcard 15:
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front: What is the significance of a non-ohmic conductor’s graph?
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back: The graph is not a straight line through the origin
indicating the voltage-current relationship is not linear.
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Flashcard 16:
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front: In an experiment
which variable is plotted on the x-axis (independent or dependent)?
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back: The independent variable is plotted on the x-axis.
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Flashcard 17:
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front: Which variable is measured and plotted on the y-axis?
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back: The dependent variable.
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Flashcard 18:
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front: What must be kept constant as a controlled variable when verifying Ohm’s Law?
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back: Temperature must be kept constant.
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Flashcard 19:
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front: What is the formula to calculate total resistance for resistors connected in series?
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back: R total = R₁ + R₂ + R₃ + ...
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Flashcard 20:
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front: How does current behave in a series circuit?
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back: The current remains the same throughout the circuit.
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Flashcard 21:
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front: How does voltage behave in a series circuit with multiple resistors?
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back: The total voltage is the sum of the voltages across each resistor.
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Flashcard 22:
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front: How does current behave in a parallel circuit?
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back: The total current splits and is the sum of currents through each branch.
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Flashcard 23:
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front: How does voltage behave in a parallel circuit across each branch?
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back: The voltage is the same across each branch.
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Flashcard 24:
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front: How do you calculate the effective resistance of resistors connected in parallel?
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back: 1/Rp = 1/R₁ + 1/R₂ + ... + 1/Rn
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Flashcard 25:
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front: What is the first step when calculating the effective resistance of a complex circuit with both series and parallel resistors?
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back: Identify the parallel resistor combinations and calculate their effective resistance.
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Flashcard 26:
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front: What is the formula to calculate electric power using voltage and current?
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back: Power (P) = Voltage (V) × Current (I)
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Flashcard 27:
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front: What is a kilowatt hour (kWh)?
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back: A kilowatt hour is a unit of energy equal to one kilowatt of power used for one hour.
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Flashcard 28:
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front: How do you convert watts to kilowatts?
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back: Divide watts by 1000.
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Flashcard 29:
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front: How do you calculate the total cost of electricity consumption?
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back: Total cost = Energy used (kWh) × Tariff (cost per kWh)
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Flashcard 30:
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front: What does the voltmeter read when connected across a battery with the switch open?
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back: It reads the electromotive force (EMF).
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Flashcard 31:
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front: What happens to the voltmeter reading across a battery when the switch is closed?
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back: It reads the external voltage (V external)
sometimes called terminal voltage.
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Flashcard 32:
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front: Define electromotive force (EMF).
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back: EMF is the maximum energy provided by a battery per unit charge passing through it.
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Flashcard 33:
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front: What causes the difference between EMF and the terminal voltage (V external) when a current flows?
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back: The internal resistance of the battery causes a voltage drop called internal voltage (V internal).
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Flashcard 34:
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front: Write the formula that relates EMF
terminal voltage
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back: EMF = V external + V internal
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Or EMF = I × R external + I × r (internal resistance)
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Or EMF = I (R external + r)
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Flashcard 35:
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front: How do you calculate the total current in a circuit that includes a battery’s internal resistance?
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back: Calculate total external resistance
add internal resistance
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I = EMF / (R external + r)
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Flashcard 36:
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front: How is the effective resistance of two resistors of 4 Ω and 6 Ω connected in parallel calculated?
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back: 1/Rp = 1/4 + 1/6 = 5/12
so Rp = 12/5 = 2.4 Ω
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Flashcard 37:
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front: Given a total voltage of 20 V and total resistance of 5 Ω
what is the total current?
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back: I = V / R = 20 V / 5 Ω = 4 A
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Flashcard 38:
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front: When calculating current through parallel resistors
how is the current split according to resistance?
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back: The smaller the resistor
the larger the current through that branch.
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Flashcard 39:
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front: What steps are used for splitting current in parallel branches using ratios?
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back: Multiply the result by each part to find current through each resistor.
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Flashcard 40:
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front: If two resistors R1=4 Ω and R2=6 Ω are connected in parallel with a total current of 4 A
what is the current through R1?
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back: Current through R1 = (3/5) × 4 A = 2.4 A
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Flashcard 41:
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front: What is the current through R2 in the previous example?
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back: Current through R2 = (2/5) × 4 A = 1.6 A
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Flashcard 42:
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front: What does an ammeter connected in series measure?
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back: It measures the total current flowing through the circuit.
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Flashcard 43:
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front: What causes the internal voltage drop within a battery?
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back: The battery’s internal resistance dissipates some energy as heat
causing the voltage drop.
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Flashcard 44:
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front: Define power
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back: "Define power as the rate at which work is done."
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Flashcard 45:
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front: State Ohm's law in words:
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back: "The potential difference across a conductor is directly proportional
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to the current in the conductor at constant temperature."
