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What is the effect of increasing the length of a wire on its resistance?
Increasing the length increases the resistance.
What is the effect of increasing the cross-sectional area of a wire on its resistance?
Increasing the cross-sectional area decreases the resistance.
What happens to the current in a circuit if the voltage is doubled, assuming resistance remains constant?
The current doubles (Ohm's Law: V=IR).
What happens to the total resistance when resistors are added in series?
The total resistance increases.
What happens to the total resistance when resistors are added in parallel?
The total resistance decreases.
What is the effect of increasing temperature on the resistivity of most materials?
Increasing temperature typically increases resistivity.
How do you calculate the equivalent resistance of resistors in series?
Add the individual resistances: R_eq = R_1 + R_2 + R_3 + ...
How do you calculate the equivalent resistance of resistors in parallel?
Use the reciprocal formula: 1/R_eq = 1/R_1 + 1/R_2 + 1/R_3 + ...
How do you calculate electric power using current and voltage?
Multiply the current by the voltage: P = IV.
How do you calculate electric power using current and resistance?
Multiply the square of the current by the resistance: P = I^2 * R.
How do you calculate electric power using voltage and resistance?
Divide the square of the voltage by the resistance: P = V^2 / R.
How do you calculate resistance (R) given resistivity (ฯ), length (L), and cross-sectional area (A)?
Use the formula: $$R = \rho \frac{L}{A}$$
How do you calculate electric power (P) using current (I) and voltage (V)?
Use the formula: $$P = IV$$. You can also use $$P = I^2R = \frac{V^2}{R}$$ if resistance is known.
Describe the steps to find the equivalent resistance of resistors in series.
Add the individual resistances: $$R_{eq} = R_1 + R_2 + R_3 + ...$$
Describe the steps to find the equivalent resistance of resistors in parallel.
1. Find the reciprocal of each resistance. 2. Add the reciprocals. 3. Take the reciprocal of the sum: $$\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + ...$$
What is Ohm's Law and how can it be applied?
Ohm's Law relates voltage, current, and resistance: $$V = IR$$. It can be rearranged to find any of the three variables if the other two are known: $$I = \frac{V}{R}$$ or $$R = \frac{V}{I}$$