If 66 MW of power at 35 kV (rms) arrives at a town from a generator via 2.6 transmission lines. Calculate the emf at the generator end of the lines. Express your answer using two significant figures. E = 4.0×104 V Submit Previous Answers Correct Part B Calculate the fraction of the power generated that is wasted in the lines. Express your answer using two significant figures. ΜΕ ΑΣΦ Fraction wasted = 0.14 Submit Previous Answers Request Answer × Incorrect; Try Again; 4 attempts remaining ? % Di

The label on a battery-powered radio recommends the use of a rechargeable nickel-cadmium cell (nicads), although it has a 1.25-V emf, whereas an alkaline cell has a 1.58-V emf. The radio has a 3.20 resistance.(a) Draw a circuit diagram of the radio and its battery. Now, calculate the power delivered to the radio (b) when using a nicad cells, each having an internal resistance of 0.0400 , and (c) when using an alkaline cell, having an internal resistance of 0.200 . (d) Does this differenceseem significant, considering that the radio's effective resistance is lowered when its volume is aimed up?

In this chapter, most examples and problems involved direct current (DC). DC circuits have the current flowing in one direction, from positive to negative. When the current was changing, it was changed linearly from I=ImaxtoI=+Imax and the voltage changed linearly from V=Vmax to V=+Vmax where Vmax=ImaxR .Suppose a voltage source is placed in series with a resistor of R = 10 that supplied a current that alternated as a sine wave, for example, I(t)=(3.00A)sin(24.00st) . (a) What would a graph of the voltage drop across the resistor V(t) versus time look like? (b) What would a plot of V(t) versus I(t) for one period look like? (Hint: If you are not sure, try plotting V(t) versus I(t) using a spreadsheet.)

A 240-kV power transmission line carrying 5.00x102. A is hung from grounded metal towers by ceramic insulators, each having a 1.00x 109- resistance. Figure 21.51. (a) What is the resistance to ground of 100 of these insulators? (b) Calculate the power dissipated by 100 of them, (c) What fraction of the power carried by the line is this? Explicitly show how you follow the steps in the Problem-Solving Strategies for Series and Parallel Resistors.

Why do transmission lines operate at very hig1 voltages while household circuits operate at fairly small voltages?

Show that the units 1 A 2 = 1W, as implied by the equation P=I 2 R.

Integrated Concepts (a) Assuming 95.0% efficiency for the conversion of electrical power by the motor, what current must the 12.0-V batteries of a 750-kg electric car be able to supply: (a) To accelerate from rest to 25.0 m/s in 1.00 min? (b) To climb a 2.00 102-m- high hill in 2.00 min at a constant 25.0-m/s speed while exerting 5.00 102 N of force to overcome air resistance and friction? (c) To travel at a constant 25.0-m/s speed, exerting a 5.00 102 N force to overcome air resistance and friction? See Figure 20.44.

(a) What is the unknown emfx in a potentiometer that balances when Rxis 10.0 O, and balances when Rsis 15.0for a standard 3.000-V emf? (b) The same emfx is placed in the same potentiometer, which now balances when Rsis 15.0for a standard emf of 3.100 V. At what resistance Rxwill the potentiometer balance?

A cauterizer, used to stop bleeding in surgery, puts out 2.00 mA at 15.0 kV. (a) What is its power output? (b) What is the resistance of the path?

(a) How much power is dissipated in a short circuit of 240-V ac through a resistance of 0.250 ? (b) What current flows?