Practice: A resistor has a current through it of 5 A. If the EMF across the resistor is 10 V, what is the resistance of this resistor?

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Intro to Current | 7 mins | 0 completed | Learn |

Resistors and Ohm's Law | 14 mins | 0 completed | Learn |

Power in Circuits | 11 mins | 0 completed | Learn |

Microscopic View of Current | 8 mins | 0 completed | Learn |

Combining Resistors in Series & Parallel | 37 mins | 0 completed | Learn |

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Practice: A resistor has a current through it of 5 A. If the EMF across the resistor is 10 V, what is the resistance of this resistor?

Practice: Two resistors are made of the same material, one twice as long as the other. If the current through the shorter resistor is 5 A, what is the current through the longer resistor if they both have the same potential difference?

0 of 5 completed

If a cylindrical metal wire is stretched to 4 times of its original length, what is the resulting resistance R, compared with the original resistance R0?
A) R = 16R0
B) R = R0/16
C) R = R0/4
D) R = 4R0

You are given a copper bar of dimensions 3 cm x 5 cm x 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the SMALLEST possible resistance, you should attach the leads to the opposite faces that measure
(a) 3 cm x 8 cm.
(b) 5 cm x 8 cm.
(c) 3 cm x 5 cm.
(d) Any pair of faces produces the same resistance.

Two pieces of metal are shaped into resistors and are connected end-to-end. The first resistor, R1, has twice the length of the second resistor, R 2, but an equal diameter. If the resistors are made of the same material, and are connected to a voltage source, what is the ratio of the voltage across each resistor, V1 / V2 ?

The headlight of a car has a resistance R = 3.4Ω. The headlight consists of a tungsten wire (resistivity p = 5.6 x 10-8 Ω • m) of length 12.4 cm. What is the cross-sectional area of the wire?

The current in a resistor decreases by 2.27 A when the voltage applied across the resistor decreases from 12.3 V to 4.26 V. Find the resistance of the resistor.
1. 0.892638
2. 4.37778
3. 7.76768
4. 3.54185
5. 2.65823
6. 4.25074
7. 4.50218
8. 3.12424
9. 3.48214
10. 5.13265

What is the resistance of a Nichrome wire at 0.0°C if its resistance is 100.00 Ω at 45°C? The temperature coefficient for nichrome is 4.00x10-4 (°C)-1A. 100.5 ΩB. 100.0 ΩC. 98.23 ΩD. 96.46 ΩE. 94.23 Ω.

A long, uniform conducting wire with resistance R is connected to the terminals of a battery with emf V, dissipating a power P. If the cross-sectional area of the wire is halved, what is the new total power dissipated?A. 2PB. ¼ PC. 4PD. ½ PE. P

Consider two conductors 1 and 2 made of the same ohmic material (ρ 1 = ρ2). Denote the length of the conductor by ℓ and the radius by r. The same voltage V is applied across the ends of both conductors. If r2 = 2 r1 , and ℓ2 = 2 ℓ1 , find the ratio I 2 / I1 of the currents.
1. I2 / I1 = 8
2. I2 / I1 = 1/2
3. I2 / I1 = 1
4. I2 / I1 = 1/4
5. I2 / I1 = 1/8
6. I2 / I1 = 2
7. I2 / I1 = 4

The length of a certain wire is doubled and at the same time its radius is increased by a factor of 4. What is the change in the resistance of this wire?A) It is reduced by a factor of 8.B) It increases by a factor of 4.C) It increases by a factor of 8.D) It is reduced by a factor of 4.

The resistivity of a 1.0 m long wire is 1.72 x 10 -8 Ωm and its cross-sectional area is 2.0 x 10-6 m2. If the wire carries a current of 0.2 A, what is the voltage across the wire?

a) Explain the distinction between an ohmic and non-ohmic material, in terms of how the current and resistance behave as the voltage difference across the material is changed.b) Now, imagine a single-loop circuit with a battery, two wires, and a 10 Ohm resistor. The wires are also ohmic, but with a resistance much smaller than the 10 Ohm resistor. Despite the disparity in resistance, the current in the wire is the same as that through the resistor since they are in series. Using Ohm's Law, explain how this uniformity in current relates to (or arises from) the individual potential differences across the wire and resistor.

Imagine a single-loop circuit with a battery, and three resistors R1, R2, R3 connected in series. Resistance is ignorable except for the resistors. Resistors are ohmic. Answer the following questions a. Which (if any) physical quantity- among resistance R, current I, and voltage V must be the same for the three resistors? b. How are R, I, and V related for each resistor in this circuit? Answer with an equation involving these three quantities.

Consider the circuit shown. (Intro 1 figure) All wires are considered ideal; that is, they have zero resistance. We will assume for now that all other elements of the circuit are ideal, too: The value of resistance is a constant, the internal resistances of the battery and the ammeter are zero, and the internal resistance of the voltmeter is infinitely large.Intro 1:Intro 2:Part A What is the reading V of the voltmeter?Express your answer in terms of the EMF ℰ. Part BThe voltmeter, as can be seen in the figure, is connected to points 1 and 3. What are the respective voltage differences between points 1 and 2 and between points 2 and 3?a) 0; ℰb) 0; -ℰc) ℰ; 0d) ℰ;ℰPart CWhat is the reading I of the ammeter?Express your answer in terms of ℰ and R.Now assume that the battery has a nonzero internal resistance r (but the voltmeter and the ammeter remain ideal). (Intro 2 figure)Part DWhat is the reading of the ammeter now?Express your answer in terms of ℰ, r, and R.Part EWhat is the reading of the voltmeter now?Express your answer in terms of ℰ, r, and R.

What is the purpose of the rheostat in the resistance and resistivity experiment?1) to limit the current in the circuit.2) to overheat.3) as an aid to adjusting the current in the circuit.4) it is the resistor whose resistance is to going to be determined.

Two identical lightbulbs are connected in series to a single 9.0 V battery.a. Sketch the circuit.b. Sketch a graph showing the potential as a function of distance through the circuit, starting with V = 0V at the negative terminal of the battery.

A. Consider a circuit containing five identical light bulbs and an ideal battery. Assume that the resistance of each light bulb remains constant. Rank the bulbs (A through E) based on their brightness.Rank from brightest to dimmest. To rank items as equivalent, overlap them.B. The switch shown is initially closed. What happens when it is opened?What happens to bulb C?a) It gets dimmer.b) It gets brighter.c) There is no change.

A 0.0075 v/m electric field creates a 3.9 mA current in a 1.0 mm diameter wire. What material is the wire made of?

Electrons moving through the circuit in the attached figure will go through the resistorA. go from a to b.B. go from b to a.

You have a circuit consisting of four 4.5 V D-cell batteries in series, some wires, and a light bulb. The bulb is lit and the current flowing through the bulb is 0.50 A. You may assume that all of the voltage drop occurs in the light bulb. What is the resistance of the bulb?

Which of the following materials is the poorest electrical conductor?A. NichromeB. CopperC. Aluminum D. Brass

The figure is a current-versus-potential-difference graph for a cylinder.What is the cylinder's resistance?

According to Table 1, which of the following materials is the best electrical conductor? Brass Copper Aluminum Nichrome

Rank in order, from largest to smallest, the resistivities ρ1 to ρ5 of these wires. Rank from largest to smallest. To rank items as equivalent, overlap them.The wires in (Figure 1) all have the same resistance; the length and radius of each wire are noted.

Which of the following will increase the resistance of a wire?Check all that apply.a) Decreasing the resistivity of the material the wire is composed of will increase the resistance of the wire.b) Increasing the length of the wire will increase the resistance of the wire.c) Decreasing the length of the wire will increase the resistance of the wire.d) Decreasing the cross-sectional area of the wire will increase the resistance of the wire.e) Increasing the cross-sectional area of the wire will increase the resistance of the wire.f) Increasing the resistivity of the material the wire is composed of will increase the resistance of the wire.

The diameter of a specific copper wire is 8.325 mm, and has a resistivity of 1.72 x 10-8Ω-m. Find the resistance of a 0.85 km length of such wire used for power transmission in Ω.

A wire of length L and cross-sectional area A has resistance R.What will be the resistance Rstretched of the wire if it is stretched to twice its original length? Assume that the density and resistivity of the material do not change when the wire is stretched.

What is the equivalent resistance between points a and b in the figure?

What is the equivalent resistance between points a and b in the figure (Figure 1)? Express your answer using one significant figure.

Both batteries in the figure are identical and all light bulbs are the same. Rank in order, from brightest to least bright, the brightness of bulbs a to c.

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