Ohm's Law: Meaning & Applications in Circuits

[franz32]

1. What is the meaning of the Ohm's Law when applied to the whole circuit and to a part of a circuit?

2. The resistance varies directly with potential difference. What should be the graph of potential difference versus resistance at constant current? How would you get the constant current out of the graph?

3. The relation between current and potential difference if the resistance is constant is that they vary directly proportional to each other. What is the graph of potential difference and current at constant resistance?

4. The current is inversely proportional to the resistance at constant voltage. What is the graph of current versus the resistance at constant voltage, line sloping downward or parabolic downward? How would you determine the value of the constant voltage from the graph "I v.s. 1/R"?

5. If Ohm's Law is not obeyed by a certain nonlinear conductor, how do we measure its resistance?

6. Why is a person more likely to get electric shock when he plugs in an appliance to the wall socket with wet hands?

7. An electronic device has a resistance which varies directly as the potential difference across it. How does the current through the device vary with the potential difference?

8. A constant potential difference of 1.5V is established between the ends of a nichrome wire and the current through it is measured at each of the following lengths:

Length (m) Current (A)
1... 4.71
2... 2.36
3... 1.57
4... 1.18
5... 0.94

If nichrome is a linear conductor, how does the resistance of nichrome vary with the length?

 

[HallsofIvy]

These look like questions that were set to see if you bothered to read the textbook. What have you done on them yourself?

 

[M98Ranger]

1. The meaning of Ohm's Law when applied to the whole circuit is that the current through a conductor is directly proportional to the potential difference across it, and inversely proportional to the resistance of the conductor. When applied to a part of a circuit, it means that the current through that part is equal to the potential difference across it divided by its resistance.

2. The graph of potential difference versus resistance at constant current would be a straight line. To determine the constant current, we can use the equation I = V/R, and plot different values of potential difference and resistance on the graph. The slope of the line would represent the constant current.

3. The graph of potential difference versus current at constant resistance would also be a straight line. To determine the constant resistance, we can use the equation R = V/I, and plot different values of potential difference and current on the graph. The slope of the line would represent the constant resistance.

4. The graph of current versus resistance at constant voltage would be a line sloping downward. This is because as the resistance increases, the current decreases, and vice versa. To determine the constant voltage, we can use the equation V = IR, and plot different values of current and resistance on the graph. The y-intercept of the line would represent the constant voltage.

5. If Ohm's Law is not obeyed by a certain nonlinear conductor, we can measure its resistance by using a multimeter. The multimeter measures the voltage and current through the conductor, and we can then use Ohm's Law to calculate the resistance.

6. A person is more likely to get an electric shock when plugging in an appliance with wet hands because water is a good conductor of electricity. This increases the current flow through the body, which can lead to an electric shock.

7. If the resistance of an electronic device varies directly with the potential difference across it, then the current through the device will also vary directly with the potential difference. This means that as the potential difference increases, the current through the device will also increase.

8. If nichrome is a linear conductor, then its resistance would vary directly with the length. This means that as the length of the wire increases, the resistance would also increase. We can see this relationship in the given data, as the current decreases as the length of the wire increases.