Physics

Please check my answers:

The voltage across a 10-ohm resistor carrying 3 amps must be? I got 30 volts-v=?, I=3 amps, R= 16 ohm. v= 30 amps * 10 ohm=30 volts

A 4-ohm resistor is connected in parallel with a 6 ohm resistor. What is the total resistance of this pair of resistors? I got 6.87 ohms
rt=r1+r2/r1+r2 = rt= 4 ohm+6ohm/4 ohm+6ohm= rt=.25+.167/.25+.167=6.87
how I got .25 and .167 its from the decimal 1/4=.25 and 1/6=.167

The power dissipated in a 4-ohm resistor carrying 3 amps is? I wasn't too sure about this one, but I got 12 watts this is how I did it: power=current * voltage, power= 4 ohm* 3 amps= 12 watts

What is a device that produces AC electricity? Why does our power grid use AC electricity? (For the first part I got an alternator and for the second part I don't understand)

  1. 👍 0
  2. 👎 0
  3. 👁 1,023
  1. 1. 30 volts is correct
    2. 6.87 is not correct
    For parallel resistors,
    1/RT = 1/R1 + 1/R2 + 1/R3...
    For two resistors, 4 ohm and 6 ohm
    1/RT = 1/4 + 1/6

    1. 👍 0
    2. 👎 0
  2. 3. 12 watts is not correct
    A 4 ohm resistor carrying 3 amps has a voltage drop of 3 * 4 or 12 volts.
    The current throught the resistor is 3 amps. Volts * Amps = 3 * 12 = 36 Watts.

    4. AC voltage is easily changed with a transformer. High voltage is good for long distance transmission since for the same power, the current is less at higher voltages. For a fixed resistance of a transmission line, high voltage/low current has lower heating losses. For consumer use, the higher voltage is converted back to the lower voltage required by most user products.

    1. 👍 0
    2. 👎 0
  3. Name a device that produces DC electricity. What does 60Hz, 120V electricity mean?

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    A 30 ohm resistor is connected in parallel with a variable resistance R. The parallel combination is then connected in series with a 6 ohm resistor and connected across a 120 V source. Find the minimum value of R if the power

  2. Physics

    A 30 ohm resistor is connected in parallel with a variable resistance R and the parallel combination is then connected in series with a 5 ohm resistor, and connected across 120 volt source. Find the minimum value of R if the power

  3. physics

    a 100 V DC signal is applied to four resistors as shown in Fig. 5. The values of the resistors are 20 ohm, 40 ohm, 60 ohm and 80 ohm. What is the voltage across the 40 ohm resistor?

  4. Science

    Use Ohm’s Law to determine the resistance in a circuit if the voltage is 12.0 volts and the current is 4.0 amps. A.8.0 ohms B. 48 ohms C.3.0 ohms** D.12 ohms

  1. physics 102

    The output voltage of an AC generator is given by Δv = (180 V) sin (70πt). The generator is connected across a 13.0-Ω resistor. (a) By inspection, what is the maximum voltage? V (b) By inspection, what is the frequency? Hz (c)

  2. science

    A thermally insulated 50 ohm resistor carries a current of 1 A for 1 s. The initial temperature of the resistor is 10 degree Celsius, its mass is 5 g, its specific heat capacity is 850. What is the change in entropy of the

  3. Physics

    Determine the total resistance of each of the following parallel circuits. A. A parallel circuit with a 20-ohm resistor and a 10-ohm resistor. B. A parallel circuit with two 20-ohm resistors and a 10-ohm resistor. C. A parallel

  4. physics (please check)

    A total resistance of 3 ohms is to be producd by combining an unknown resistor R with a 12 ohm resistor. What is the value of R and how is it connected to the 12 ohm resistor a) 4.0 ohm parallel b) 4.0 ohm in series c) 2.4 ohm in

  1. physics

    Given a 10-V power supply, would a 20-ohm resistor and a 5-ohm resistor need to be arranged in parallel or in series to generate a current of 2.5 A? How much current would move through each resistor?

  2. physics

    Calculate the total resistance for a 650 ohm, a 350 ohm, and a 1000 ohm resistor connected in series.

  3. physics

    a 20 ohm and 60 ohm resistors are connected in series to a DC generator. The voltage across the 20 resistor is 80 volts. The current through the 60 ohm resistor? A) 1.0A B) 5.0 A C) is about 1.3 A D)4.0 A E) cannot be calculated

  4. Physics

    your electronics friend needs a 20-ohm resistor but has only 40-ohm resistors. He tells you that he can combine them to produce a 20-ohm resistor. how?

You can view more similar questions or ask a new question.