50. the time constant of a capacitor is:
a. directly proportional to the resistance in the circuit.
b. the time required to charge to 63% or discharge to 37%.
c. directly proportional to the capacitance in the circuit.
d. all of these.

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa.s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)