The resistivity of blood is related to its hematocrit, the volume fraction of red blood cells in the blood. A commonly used equation relating the hematocrit h the blood resistivity ρ (in Ω⋅m) is ρ=1.32/(1−h)−0.79. In one experiment, blood filled a graduated cylinder with an inner diameter of 0.90 cm. The resistance of the blood between the 1.0 cm and 2.0 cm marks of the cylinder was measured to be 210 Ω. What was the hematocrit for this blood?

Nerve impulses are carried along axons, the elongated fibers that transmit neural signals. We can model an axon as a tube with an inner diameter of 10 μm. The tube wall is insulated, but the fluid inside it has a resistivity of 0.50 Ω⋅m. What is the resistance of a 5.0-mm-long axon?

A 19.5-g sample of nichrome with density 8.400 ✕ 103 kg/m3 is made into a wire 1.45 ✕ 103 m long. If the resistivity of nichrome is 1.000 ✕10−6 Ω · m, what is the resistance of this wire?

A digital thermometer employs a thermistor as the temperature-sensing element. A thermistor is a kind of semiconductor and has a large negative temperature coefficient of resistivity α. Suppose α = -0.0503 (Co)-1 for the thermistor in a digital thermometer used to measure the temperature of a patient. The resistance of the thermistor decreases to 87.6% of its value at the normal body temperature of 37.0 oC. What is the patient's temperature?

A copper wire of radius a = 0.240 mm has an aluminum jacket of outer radius b = 0.329 mm. There is a current i = 1.57 A in the composite wire. Take the resistivity for copper and aluminum to be 1.69 × 10-8Ω·m and 2.75 × 10-8Ω·m. Calculate the current in (a) the copper and (b) the aluminum. (c) If a potential difference V = 13.1 V between the ends maintains the current, what is the length in meters of the composite wire?

Question 3: A platinum resistance thermometer is a device that allows us to determine the temperature by measuring the resistance of a piece of pure platinum wire. In the interval between the freezing point of water and 700.0°C, the relationship between the resistance and the Celsius temperature Tc is accurately captured by the formula R = Ro (1 + A Tc + B (Tc)²) where A and B are constants determined by measurements at the ice point of water, the steam point of water, and the melting point of zinc (419.514°C). (a) If R equals 10.000 ohms at the freezing point of water, 13.946 ohms at the boiling point of water, and 24.174 ohms at the melting point of zinc, find RO, A, and B (b) If the resistance is measured to be 17.7 ohms, what is the temperature? (c) Plot R versus Tc in the range from 0°C to 700.0°C. Math tip: When we have several equations for several unknown variables, we can use the first equation to solve for one of the variables in terms of the others and then replace that…

In a physics project, you need a wire to electrically heat a cryostat. You decide to create one with materials you have lying around. You find a 29.0-g piece of copper. The resistivity of copper is 1.68 x 10-8 Ω.m, and its density is 8.9 g/cm3. You will need to use all of your copper to create a solid cylindrical wire that has a total resistance of 0.75 Ω.Determine how long your wire will be, and what its diameter will be.

The graph below shows data for a wire that is 9 m long & has a cross-sectional area of 0.002 m². The wire is made from an unknown material. Determine the resistivity of the material and the power loss of the wire when the current is 100 A. VOLTAGE vs. CURRENT GRAPH V (V) 500 400 300 200 100 20 40 60 80 1 (A) 100 resistivity of wire = power loss (when I = 100 A) = ABACHER 2-m

As part of a class project you are given 0.900 g of copper and asked to fabricate a wire with uniform cross-section. You use up 95% of the copper and make a wire with a resistance of 0.723 Ω. The resistivity of copper is 1.72  10-8 Ω · m and its density is 8.92  103 kg/m3. (a) What length of wire do you end up with? (m)(b) What is the diameter of the wire? (mm)

A copper wire of radius a = 0.256 mm has an aluminum jacket of outer radius b = 0.337 mm. There is a current i = 1.59 A in the composite wire. Take the resistivity for copper and aluminum to be 1.69 × 10-8Ω·m and 2.75 × 10-8Ω·m. Calculate the current in (a) the copper and (b) the aluminum. (c) If a potential difference V = 15.0 V between the ends maintains the current, what is the length in meters of the composite wire?