2nd year Lesson 10 Reviewing of DC Theory

A device operates on 208 volts and draws 8.0 amperes. How much power does this device consume in watts?

1,664

A circuit has an operating voltage of 480 volts. The circuit resistance is 60 ohms, which limits the current to eight amperes. In order to increase the resistance to limit the current to four amperes, how much total resistance is needed in this circuit?

120 Ω

What is the total resistance of the following circuit? E(s) = R(1) R(2) R(3) ES = 4,160 voltsR1 = 1,000 ohmsR2 = 4,500 ohmsR3 = 6,500 ohms

12000 ohm

How much power would be consumed in a parallel circuit that has a source voltage of 480 volts and a total circuit current of 35 amperes?

16.8 kW

Solve for the total resistance of the following circuit. E(s)= R1-R2-R3

18.46 Ω

If the circuit voltage is 12,500 volts and the circuit current is 6.25 amperes, the resistance of the circuit would be ? .

2,000 Ω

If two 480-volt power sources are connected in parallel to supply a 24-ohm load, how much current will flow in the circuit?

20 A

A 1,000-watt lamp operates on 277 volts. How much current will this lamp draw?

3.61 A

What is the total current of the following circuit? E(s) R1

3A

Semiconductors have ? electrons in the valence shell.

4

If the current of a circuit is 4.16 milliamperes and the resistance is one megohm, the voltage of this circuit would be ? .

4.16kv

A circuit contains four 160-ohm resistors in parallel. What is the circuit resistance? (Use the rule for determining total resistance with resistances of equal value)

40 Ω

If a circuit has three branches with currents of 120 amperes, 180 amperes, and 150 amperes, what would be the total current of this circuit?

450A

How much current will flow through a 2.76-kilohm resistor when 13.8 kilovolts are applied?

5.0Ω

If 600 volts is delivered to a circuit that has a resistance of four ohms, how much power would be consumed by the load?

90 kW

The ampere, or amp, is a measure of current flow and is represented by the letter ? .

A

When resistors are connected in series, their values are ? to determine total resistance.

Added

The greater the voltage across a fixed resistor, the greater the ? through that resistor.

Current

An increase in the total resistance of a series circuit will cause a(n) ? in the current of that circuit.

Decrease

The ? method is used to determine the total power in a parallel circuit when the power is determined from the total current, total resistance, and source voltage.

Direct

Voltage is also known as ? force.

Electromotive

Adding parallel loads to a circuit will increase the total circuit resistance and decrease the total circuit current.

False

Electrical energy use is measured in ampere-hours which involves how much power is used with respect to time.

False

In series-opposing power sources, the power sources are connected so their polarities are in the same direction.

False

Like charges attract each other and unlike charges repel each other.

False

The formula for determining the total resistance in a parallel circuit is: R(t)= 1/r+1/r2+1/r3

False

The proton and electron combine to form the atom's nucleus.

False

Current flowing through a conductor will produce both ? and a magnetic field.

Heat

Electrical energy can produce ? .

Heat

In calculations, current is represented by the letter ? .

I

The heat produced by the current flowing through the resistance in a circuit is called ? losses.

I(2)R

Which of the following is the correct formula for determining the total current in a circuit?

I(t)=E/R

A(n) ? is a material whose electrons strongly oppose movement.

Insulator

Any current-carrying conductor will create a(n) ? field.

Magnetic

The electron has an electrical charge with a(n) ? polarity.

Negative

The mathematical relationship among current (I), voltage (E), and resistance (R) is called ? Law.

Ohm's Law

A series circuit has ? current path(s).

One

The ? is one of the three main parts of an atom.

Proton

Which of the following is the product-sum formula for determining total resistance in parallel circuits containing two unequal resistances?

R(T)= R1R2/R1+R2

As the current flows through each component in a series circuit, it will ? .

Remain the same

What opposes current flow in an electrical circuit?

Resistance

RT = R1 + R2 +...+ RN is the formula for determining the total resistance in a ? circuit.

Series

In a series circuit, the total voltage source is equal to the algebraic ? of the individual voltage sources.

Sum

Adding additional resistors in parallel with those resistors already existing in a parallel circuit will always decrease the total resistance of the circuit.

True

Branch currents in a parallel circuit are always less than the total current of the circuit.

True

Friction was the first known method of generating electricity.

True

If the voltage in a given circuit is increased, the current will increase; but if the resistance is increased, then the current will decrease.

True

In a circuit, current is directly proportional to voltage and inversely proportional to resistance.

True

Ohm's law states that one volt will push one ampere through one ohm of resistance.

True

The ? is a unit of electromotive force that pushes electrons through a conductor and is represented by the symbol V.

Volt

? is a potential difference in electron charges.

Voltage

A unit of electrical power is the ? and is represented in equations as the letter P.

Watt

One horsepower is equal to approximately 746 ? .

Watts

A(n) ? is a material whose electrons can be moved with relative ease.

conductor

Current is defined as the flow of ? through a material.

electrons

The primary source of electrical power is ? .

magnetism

The ? is a unit of resistance in a circuit and is represented by the symbol for omega.

ohm

Which of the following formulas is the correct expression of Ohm's Law for power?

p=exi

Friction is a source of ? electricity.

static