Electric Current Explanation Find Here

A hollow, conducting sphere with an outer radius of 0.250 m and an inner radius of 0.200 m has a uniform surface charge destiny of ${\displaystyle +6.37\times {10}^{-6}\frac{C}{m^2}}$. A charge of ${\displaystyle -0.500\mu C}$ is now introduced at the center of the cavity inside the sphere. 
(a) What is the new carge density on the outside of the sphere? 
(b) Calculate the strength of the electric field just outside the sphere. 
(c) What is the electric flux through a spherical surface just inside the inner surface of the sphere?

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 water pump that consumes 2 kW of electric power when operating is claimed to take in water from a lake and pump it to a pool whose free surface is 30 m above the free surface of the lake at a rate of 50 L/s. Determine if this claim is reasonable.

A well-insulated rigid tank contains 3 kg of saturated liquid-vapor mixture of water at 200 kPa. Initially, three-quarters of the mass is in the liquid phase. An electric resistance heater placed in the tank is now turned on and kept on until all the liquid in the tank is vaporized. Determine the entropy change of the steam during this process. Answer: 11.1 kJ/K

Flux through a Cube (Eigure 1) A cube has one corner at the origin and the opposite corner at the point (L, L, L). The sides of the cube are parallel to the coordinate planes

A slab of insulating material of uniform thickness d, lying between ${\displaystyle \frac{-d}{2}}$ to ${\displaystyle \frac{d}{2}}$ along the x axis, extends infinitely in the y and z directions, as shown in the figure. The slab has a uniform charge density ${\displaystyle \rho }$. 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 $E_{vec}$ at the surface of one side of the slab?

Answer the following T/F questions based on the behavior of the circuit in the above Figure 5:
(1) A transient current flows for a short time after the RELAY is switched to either the N.O.("normally open") or N.C. ("normally closed") position.
(2)The transient currents that flow in this experiment decays exponentially to zero.
(3)The capacitor charge Q exponentially decays to zero when the RELAY is thrown to position N.O.
(4)When the current I is positive, the capacitor charge Q is decreasing.
(5)When the current I is positive, the measured VOLTAGE IN 2 will be negative.
(6)When the capacitor charge Q is positive, the measured VOLTAGE IN 1 is positive.
(7)The quantity t1/2=? ln 2 is called the half-life of an exponential decay, where ?=RC is the time constant in an RC circuit. The current in a discharging RC circuit drops by half whenever t increases by ${\displaystyle t_{\frac{1}{2}}}$. For a circuit with R=2 k? and C=3 ?F, if the current is 6 am at t=5 ms, at what time (in ms) will the current be 3 mA?

A person who starting from rest at the top of a cliff swings down at the end of a rope,releases it, and falls into the water below. There are two paths bywhich the person can enter the water. Suppose he enters the waterat a speed of 13 m/s via path 1. How fast is he moving on path 2 when he releases the rope at a height of 5.20 m above the water? Ignore the effects of air resistance.

A 12-V battery is connected to terminals A and B in the above Figure.
(a) Given that R = 75 ohms, find the current in each resistor.
(b) Suppose the value of R is increased. For each resistor in turn, state whether the current flowing through it increases or decreases. Explain.

Two resistors, A and B, are connected in parallel across a 6.0V battery. The current through B is found to be 2.0 A. When the two resistos are connected in series to the 6.0 V battery,a voltmeter connected across the resistor A measures a voltage of4.0 V. Find the resistances of A and B.

(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.

 
Consider the three circuits shown above. All the resistors and all the batteries are identical. Which of the statements are true and which ones are false? 
1)The power dissipated in circuit A is twice the power dissipated in circuit B. 
2) The current through a resistor is the same in circuits A and C. 
3) The current through a resistor is the same in circuits A and B. 
4) The voltage across a single resistor in circuit C is twice the voltage across a single resistor in circuit B. 
5) The total power dissipated in circuit C is twice the total power dissipated in circuit B.