Homework 9.5 A conducting sphere of radius a is enclosed by a conducting spherical shell of radius 6 (b > a). What is the capacitance C of such a device? Now suppose the Space in between is lled with a weakly conducting material of conductivity 0'. If a voltage V is applied between the two conductors, calculate the total current owing through them. What is the resistance R of this device? What is the product of R and 0'? Suppose the device is charged up to a voltage V0 by a battery. At time t : 0, the battery is disconnected, nd the voltage as a function of 6. How long does it take to halve the voltage