Question

Problem 22.67

It's possible to estimate the percentage of fat in the body by measuring the resistance of the upper leg rather than the upper arm; the calculation is similar. A person's leg meas-ures 40 cm between the knee and the hip, with an average leg diameter (ignoring bone and other poorly conducting tissue) of 12 cm. A potential difference of 0.76 V causes a current of 1.6 mA .

Part A

What are the fractions of muscle and fat in the leg?

Express your answer using two significant figures separated by a comma.

Answer 1

Solution The laver of fat and muscle are parallel to each other, hence their resistances can be assumed to be connected in parallel Using the values, pf= 25 and Pm-13 Ωm for the resistivities of fat and muscle respectively and assuming fm to be the fraction of muscle, we have, ρί