Paul Peter Urone; Roger Hinrichs

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19.1 Ohm's law

61 .

Explain how current and charge are related, including how direction is defined.

Electric current is the charge that passes through a conductor per unit time. The direction of the current is defined to be the direction in which positive charge would flow.
Electric current is the charges that move in a conductor. The direction of the current is defined to be the direction in which positive charge would flow.
Electric current is the charge that passes through a conductor per unit time. The direction of the current is defined to be the direction in which negative charge would flow.
Electric current is the charges that move in a conductor. The direction of the current is defined to be the direction in which negative charge would flow.

62 .

What could cause Ohm's law to break down?

If small amount of current flows through a resistor, the resistor will heat up so much that it will change state, in violation of Ohm’s law.
If excessive amount of current flows through a resistor, the resistor will heat up so much that it will change state, in violation of Ohm’s law.
If small amount of current flows through a resistor, the resistor will not heat up so much and it will not change its state, in violation of Ohm’s law.
If excessive amount of current flows through a resistor, the resistor will heat up so much that it will not change its state, in violation of Ohm’s law.

63 .

You connect a single resistor

R

across a

10\text{-V}

battery and find that

0.01\,\text{A}

flows through the circuit. You add another resistor

R

after the first resistor and find that

0.005\,\text{A}

flows through the circuit. If you have

10

resistors

R

connected in a line one after the other, what would be their total resistance?

$\frac{R}{10}$
$5\,\text{R}$
$\frac{10}{R}$
$10\,\text{R}$

19.2 Series Circuits

64 .

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

Circuit diagram with a battery and a resistor.

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.

65.

What is the current through each resistor in the circuit?

The figure shows a circuit with five vertical branches connected at the top and bottom. The bottom is also connected to ground. From left to right, the branch elements are 50-ohm R 1, 80-ohm R 2, 24-volt voltage source, 20-ohm R 3, and 100-ohm R 4, respectively.

Current through resistors R₁, R₂, R₃, and R₄ is 0.48 A, 0.30 A, 1.2 A, and 0.24 A, respectively.
Current through resistors R₁, R₂, R₃, and R₄ is 1200 A, 1920 A, 480 A, and 2400 A, respectively.
Current through resistors R₁, R₂, R₃, and is R₄ 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.

In a house, a single incoming wire at a high potential with respect to the ground provides electric power. How are the appliances connected between this wire and the ground, in parallel or in series? Explain.

The appliances are connected in parallel to provide different voltage differences across each appliance.
The appliances are connected in parallel to provide the same voltage difference across each appliance.
The appliances are connected in series to provide the same voltage difference across each appliance.
The appliances are connected in series to provide different voltage differences across each appliance.

19.4 Electric Power

67 .

A single resistor is connected across the terminals of a battery When you attach a second resistor in parallel with the first, does the power dissipated by the system change?

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

68 .

In a flashlight, the batteries are normally connected in series. Why are they not connected in parallel?

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.

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