Solved: Figure 26-35a shows a rod of resistive material.

Chapter , Problem 54

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Figure 26-35a shows a rod of resistive material. The resistance per unit length of the rod in- (a) -' I--,\' (m) creases in the positive direction of 0 1.0 the x axis. At any position x along --II-- do\' row the rod, (differential) the resistance section dR of of a width nar- (b) ~ n~ dx is given by dR = 5.00x dx, (c) V n where dR is in ohms and x is in U meters. Figure 26-35b shows such a narrow section. You are to slice off Fig.26-35 54. PROBLEMS 703 a length of the rod between x = 0 and some position x = Land then connect that length to a battery with potential difference V = 5.0 V (Fig. 26-35c). You want the current in the length to transfer energy to thermal energy at the rate of 200 W. At what position x = L should you cut the rod?