Question

State Ohm's law in words. For what type of circuit elements does it correctly describe the...

State Ohm's law in words. For what type of circuit elements does it correctly describe the behavior?

Does a light bulb have a constant resistance? Explain. Is a light bulb ohmic?

Does a resistor have a constant resistance? Explain. Is a resistor ohmic?

Homework Answers

Answer #1

. Ohm's Law deals with the relationship between voltage and current in an ideal conductor. This relationship states that:

The potential difference (voltage) across an ideal conductor is proportional to the current through it.

The constant of proportionality is called the "resistance", R.

Ohm's Law is given by:

  • V = I R

where V is the potential difference between two points which include a resistance R. I is the current flowing through the resistance. For biological work, it is often preferable to use the conductance, g = 1/R; In this form Ohm's Law is:

  • I = g V

2. Material that obeys Ohm's Law is called "ohmic" or "linear" because the potential difference across it varies linearly with the current.

3. Ohm's Law can be used to solve simple circuits. A complete circuit is one which is a closed loop. It contains at least one source of voltage (thus providing an increase of potential energy), and at least one potential drop i.e., a place where potential energy decreases. The sum of the voltages around a complete circuit is zero.

4. An increase of potential energy in a circuit causes a charge to move from a lower to a higher potential (ie. voltage). Note the difference between potential energy and potential.

Because of the electrostatic force, which tries to move a positive charge from a higher to a lower potential, there must be another 'force' to move charge from a lower potential to a higher inside the battery. This so-called force is called the electromotive force, or emf. The SI unit for the emf is a volt (and thus this is not really a force, despite its name). We will use a script E, the symbol , to represent the emf.

a)

A light bulb is not an ohmic resistor since the current through it varies NON-LINEARLY with the applied voltage.

Ohmic resistors have a linear relationship between applied voltage and the resulting current.

b)

The term, ohmic resistor, is actually a redundancy. Resistors by definition have a (more or less) constant resistance, expressed in ohms. Other devices whose resistance is dependent on some variable have other, distinct, designations. Thermistors show a great variation (sometimes negative) with temperatures, and varistors show a large variation of resistance with applied voltage.

It can be argued that all resistors are thermistors, since all known materials have resistivities which vary with temperature, so ohmic resistor might be used to refer to an ideal resistor, whose resistance would be invariate under all conditions.

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
describes what happens to the resistance of the light bulb as the voltage is increased. Explain...
describes what happens to the resistance of the light bulb as the voltage is increased. Explain please as to why the resistance changes. Does it follow Ohm's Law? Describe how the resistance of the zener diode changes as the voltage increases. Why are zener diodes not ohmic devices?
Design an experiment that verifies Ohm's Law. In other words, describe (in a sentence or two)...
Design an experiment that verifies Ohm's Law. In other words, describe (in a sentence or two) how you would conduct such an experiment using the fixed resistor and variable voltage source. Identify your dependent and independent variables and sketch a plot with the independent variable on the x-axis and the dependent variable on the y-axis. Include axes labels and the slope term of the sketched plot and relate this to Ohm's Law.
1.In your Ohm's law lab if you let the current (I) in your circuit remain constant,...
1.In your Ohm's law lab if you let the current (I) in your circuit remain constant, what will happen to the voltage (V) if the resistance (R) is tripled? 2.If you connect a 10-Volt supply voltage across a parallel combination of two 10 Ohm resistors, what should be the ammeter reading connected in series with the voltage source? 3.When you check a 7-Amps reading on your multimeter connected in series with a 3 Ohm resistor, what will the voltmeter reading...
State Mendel's Second Law, the Law of Independent Assortment and what does the law mean in...
State Mendel's Second Law, the Law of Independent Assortment and what does the law mean in terms of the gametes produced by an individual? Explain how the behavior of chromosomes in meiosis provides the basis of independent assortment.
Suppose you have a circuit with a 10 volt battery hooked up to a 100 ohm...
Suppose you have a circuit with a 10 volt battery hooked up to a 100 ohm light bulb and a variable resistor of R ohms. The light bulb and the resistor can be hooked up in series or parallel. Draw both these circuits and label them as series or parallel and with the values of each component. Now, solve for the current in the light bulb in each of these circuits for R = 10, 100, and 1000 Ohms. Given...
Please explain in your own words, what authorities does the State Government have? Please don't copy...
Please explain in your own words, what authorities does the State Government have? Please don't copy paste from a website.
1. Describe, in your own words, the Phillips Curve. What does the slope of the Phillips...
1. Describe, in your own words, the Phillips Curve. What does the slope of the Phillips curve tell you? Draw the curve and mark the axes correctly. 2. Consider a very flat (almost horizontal) Phillips curve. What could go wrong if policymakers looked only at inflation rates to determine if an intervention in the economy is required?
1) Describe opportunity identification for the entrepreneur. 2) In your own words, state what is meant...
1) Describe opportunity identification for the entrepreneur. 2) In your own words, state what is meant by the term innovation. 3) Name, and describe in detail one of the major misconceptions commonly associated with innovation. 4) Explain the challenges in new venture development. 5) Provide an example of a financial decision that can cause a new venture to fail. Explain in detail. 6) How can asking the right questions help an entrepreneur evaluate a new venture? What sort of questions...
describe the typical composition and procedural process of an appellate court. what type of argumentation does...
describe the typical composition and procedural process of an appellate court. what type of argumentation does an appellate court hear? Why are appellate court decisions important to judiciary? Explain
1.What famous royal figure attended a formal lecture given by Michael Faraday in the lat 1700’s...
1.What famous royal figure attended a formal lecture given by Michael Faraday in the lat 1700’s at the Royal Institute? 2. The metropolitan water district supplies power to what major US city? 3. One Ampere is one Coulomb of charge flowing through a circuit in how many seconds? 4. Oerstead used the current flowing in a wire due to a voltaic pile to show the link between electricity and magnetism, today simply known as _________________________. 5. Wheatstone and Ohm showed...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT