5. A resistor is made out of a solid metal sphere of radius r by cutting off its “poles" as shown in Fig. 5. The resistivity of the material is p. Figure 5 also shows how the resistor is attached to the outside circuit (establishing the direction of the current flow). Find the resistance R of this resistor with a variable cross-section. If the voltage drop across this resistor equals to V, what is magnitude E of the driving electric field right at the center of the resistor? a а Figure 5: Illustration for problem 5.

5. A resistor is made out of a solid metal sphere of radius r by cutting off its “poles" as shown in Fig. 5. The resistivity of the material is p. Figure 5 also shows how the resistor is attached to the outside circuit (establishing the direction of the current flow). Find the resistance R of this resistor with a variable cross-section. If the voltage drop across this resistor equals to V, what is magnitude E of the driving electric field right at the center of the resistor? a а Figure 5: Illustration for problem 5.