A capacitor is charged to a potential of 12.0 V and is then connected to a voltmeter having an internal resistance of . After a time of 4.00 s the voltmeter reads 3.0 V.
What are (a) the capacitance and (b) the time constant of the circuit?
An oil pump is drawing 44 kW of electric power while pumping oil with ρ= 860 kg/m^3 at a rate of 0.1 m^3/s. The inlet and outlet diameters of the piper are 8 cm and 12 cm, respectively. If the pressure rise of oil in the pump is measured to be 500 kPa and the motor efficiency is 90 percent, determine the mechanical efficiency of the pump.
(a) Determine the electric field E at the origin O in Figure due to the two charges at A and B. (Type your answer using k for proportionality constant, Q for charge and L for the length l.)
(b) Repeat, but let the charge at B be reversed in sign.
A slab of insulating material of uniform thickness d, lying between to along the x axis, extends infinitely in the y and z directions, as shown in the figure. The slab has a uniform charge density . The electric field is zero in the middle of the slab, at x=0. Which of the following statements is true of the electric field at the surface of one side of the slab?