Podcast
Questions and Answers
What is the basis for declaring the direction of electric current in a circuit?
Which of the following will affect the effect of electric shock in the human body?
Which of the following conductors has the highest resistance?
In American wire gauge (AWG), as the number gauge increases, what happens to the wire diameter?
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What is the value of the resistor with color coded Green-Blue-Red-Gold?
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What is the new resistance of a cylindrical copper rod if it is reformed to twice its original length with no change in volume?
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Determine the operating temperature of a tungsten filament bulb that draws 0.5 Amp at 110 Volts.
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Study Notes
Electric Current
- The direction of electric current in a circuit is conventional, meaning it's defined by the flow of positive charges, even though electrons (negatively charged) are the actual carriers.
Electric Shock
- Current flowing through the body is the primary factor determining the severity of an electric shock.
Resistance of Conductors
- Manganin has the highest resistance among the listed conductors, with a resistivity of $4.82 \times 10^{-7} \Omega \cdot m$.
American Wire Gauge (AWG)
- As the AWG number increases, the wire diameter decreases.
Resistor Color Codes
- Green-Blue-Red-Gold translates to a resistor with a value of 5,600 ohms with a 5% tolerance.
Copper Bar Resistance
- The resistance of a copper bar depends on its dimensions and resistivity.
- The formula for calculating resistance is R = (ρL) / A, where R is resistance, ρ is resistivity, L is length, and A is cross-sectional area.
Resistance and Volume
- If a cylindrical copper rod is reformed to twice its original length without changing its volume, its resistance will increase fourfold (4R).
Series Resistance
- When nine identical wires are connected in series, the equivalent resistance is the same as a single wire with the same length but a diameter three times larger (3d).
Filament Temperature
- The operating temperature of the tungsten filament in a light bulb can be calculated using the temperature coefficient of resistance.
- The higher the temperature, the higher the resistance.
Momentary Current
- The momentary current drawn by a lamp when it is first switched on is higher than the steady-state current because the filament is initially cold and has lower resistance.
Voltage Drop in DC Motors
- The allowable voltage drop in a DC motor is typically a percentage of the input voltage.
- This voltage drop is caused by the resistance of the wires supplying the motor.
Potential Energy Dimensions
- If the fundamental dimensions are force (F), velocity (V), and time (T), then the dimensions of potential energy are FVT.
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Description
Test your understanding of electric current, resistance, and shock severity in this quiz. Explore topics like conventional current direction, the properties of conductors, and resistor color codes. Perfect for physics students looking to reinforce their knowledge.
