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A 1 phase 400 V 6 kW load having a lagging power factor of 0.8 is supplied through a line (on 200 V side) of impedance (0.10+j0.3) Ω and a 1 phase 10 kVA 200/400 V , 50 Hz Transformer. Equivalent impedance of Transformer referred to the 400 V side is (0.2875+j1.125) Ω. Determine the source voltage required at the beginning of the line if load voltage is maintained at 400V.
A parallel plate capacitor has its plates separated with a slab of 4mm thickness and a dielectric
constant of 3. If the capacitance is to be one-third of the original value when a second slab of
6mm thickness is inserted between the plates, what should be the relative permittivity of the
second slab?
The Electron and the proton have opposite signs, so the electric force between the particles is attractive. The ratio F electric/Fg= 2×10^39; hence , the gravitational force between the particles is negligible compared with the electric force between them. Because each force is inversely proportional to distance squared, their ratio is independent of the distance between the two particles
A stent is a cylindrical tube, often made of metal mesh, that’s inserted into a blood vessel to overcome a constriction. It’s sometimes necessary to heat the stent after insertion to prevent cell growth that could cause the constriction to recur. One method is to place the patient in a changing magnetic field, so that induced current sheat the stent. Consider a stainless-steel stent 12 mm long by 4.5 mm in diameter, with total resistance 41 mΩ. Treating the stent as a wire loop in the optimum orientation,find the rate of change of magnetic field needed for a heating power of 250 mW.
A conducting loop with area 0.15 m2and resistance 6.0 Ω lies in the x−y plane. A spatially uniform magnetic field points in the + z direction. The field varies with time according to B_z=at2−b, where a= 2.0 T/s2andb= 8.0 T. Find the loopcurrent magnitude and direction
(a) at t= 3.0 s and
(b) when B_z= 0 T.
16.) The superconducting solenoid in an MRI scanner has inductance 342 mH and normally carries 1.85 kA. Copper conductors with resistance 21.6 mΩ are embedded in the superconducting coils. If superconductivity is suddenly lost and copper takes over the conduction, how long will it take for the current to drop below 250 A?
The current in an inductor is changing at 110 A/s and the inductor emf is 45 V. What is the inductance of the inductor?
A 6.0 kg object that is 3.0 m from the surface of the Moon has 28.8 J of gravitational potential energy. What is the value of g?
(Gravitational field strength/Gravitational acceleration)
Stuck trying to reverse logic this problem... If anyone has any steps using Eg=mgh I would appreciate it.
[G 7.24) An alternating current Io cos (wt) (amplitude 0.5 A, frequency 60 Hz) flows down a straight wire, which
runs along the aris of a toroidal coil with rectangular cross section (inner radius 1 cm, outer radius 2 cm, height 1
cm, 1000 turns). The coil is connected to a 500 ohm resistor.
(a) In the quasistatic approximation, what emf is induced in the toroid? Find the current, I, (t), in the resistor.
b) Calculate the back emf in the coil, due to the curent I, (t). What is the ratio of the amplitudes of this back emf
and the "direct" emf in ( a ) ?
What is the total electric flux through a closed surface containing a 2.0 uC charge?
