### Extended Response

### 19.1 Ohm's law

- Current is the ratio of charge passing through a conductor per unit time. The currentâ€™s direction is the direction in which protons would flow.
- Charge is the ratio of current passing through a conductor per unit time. The chargeâ€™s direction is the direction in which protons would flow.
- Current is the product of charge passing through a conductor and the amount of time that passes. The currentâ€™s direction is the direction in which electrons would flow.
- Charge is the product of current passing through a conductor and time. The chargeâ€™s direction is the direction in which electrons would flow.

- If the amount of current flowing through the material is too low, the resistor may heat up, creating a nonlinear relationship between current and voltage.
- If the amount of current flowing though the material is too high, the resistor may heat up, creating a nonlinear relationship between current and voltage.
- If the amount of current flowing through the material is too low, the resistor may not warm up enough to allow a nonlinear relationship between current and voltage.
- If the amount of current flowing through the material is too high, the resistor may not warm up enough to allow a nonlinear relationship between current and voltage.

- $\frac{R}{10}$
- $5\phantom{\rule{thinmathspace}{0ex}}\text{R}$
- $\frac{10}{R}$
- $10\phantom{\rule{thinmathspace}{0ex}}\text{R}$

### 19.2 Series Circuits

Explain why the current is the same at all points in the circuit below.

- If the current were not constant, the mobile charges would bunch up in places, which means that the voltage would decrease at that point. A lower voltage at some point would push the current in the direction that further decreases the voltage.
- If the current were not constant, the mobile charges would bunch up in places, which means that the voltage would increase at that point. But a higher voltage at some point would push the current in the direction that decreases the voltage.
- If the current were not constant, the mobile charges would bunch up in places, which mean that the voltage would increase at that point. A higher voltage at some point would push the current in the direction that further increases the voltage.
- If the current were not constant, the mobile charges would bunch up in places, which mean that the voltage would decrease at that point. But a lower voltage at some point would push the current in the direction that increases the voltage.

What is the current through each resistor in the circuit?

- Current through resistors
*R*_{1},*R*_{2},*R*_{3}, and*R*_{4}is 0.48 A, 0.30 A, 1.2 A, and 0.24 A, respectively. - Current through resistors
*R*_{1},*R*_{2},*R*_{3}, and*R*_{4}is 1200 A, 1920 A, 480 A, and 2400 A, respectively. - Current through resistors
*R*_{1},*R*_{2},*R*_{3}, and is*R*_{4}2.08 A, 3.34 A, 0.833 A, and 4.17 A, respectively. - The same amount of current, 0.096 A, flows through all of the resistors.

### 19.3 Parallel Circuits

- All outlets on the circuit have the same voltage because they are wired in parallel.
- All outlets on the circuit have the same voltage because they are wired in series.
- Outlets further away from the source have a lower voltage because they are wired in parallel.
- Outlets further away from the source have a lower voltage because they are wired in series.

### 19.4 Electric Power

- No, the power dissipated remain same.
- Yes, the power dissipated increases.
- Yes, the power dissipated decreases.

- Batteries are connected in series for higher voltage and power output.
- Batteries are connected in series for lower voltage and power output.
- Batteries are connected in series so that power output is a much lower for the same amount of voltage.
- Batteries are connected in series to reduce the overall loss of energy from the circuit.