Basic Electrical Midterm

It requires ________ volt(s) to push 1 ampere through 1 ohm of resistance.

1

If a 12-volt battery is connected to a series circuit with three resistors of 2 ohms, 4 ohms, and 6 ohms, how much current will flow through the circuit?

1 amp

Most carbon resistors indicate their electrical resistance by ________.

Color coded markings

Electrical controls such as switches ________.

Control electrical flow in the circuit and May be on either the source or ground side of the circuit

If the resistance and the voltage are known, what is the formula for finding the current (amperes)?

I = E/R

The fact that voltage can be created by exerting force on a crystal is used for which type of sensor?

Knock Sensor (KS)

A sheet metal screw holding a metal body panel has pierced the insulation of a power wire and is touching the copper strands. This is known as a ________.

Short to Ground

An electrical circuit uses 12 volts and has a current flow of 2 amps. What is the wattage?

24 watts

If 12 volts are being applied to a resistance of 3 ohms, ________ amperes will flow.

4

Insulators lose electrons in their outer shell easier than conductors.

False

Corrosion on electrical terminals may cause ________.

Lights to be dimmer than normal

More electrical current will flow through the branch of a parallel circuit with the ________ resistance.

Lowest

An open circuit ________.

May be caused by a blown fuse

Electrical power is calculated by ________.

Multiplying volts by current

A shorted circuit ________. A. Could include an open circuit B. Always causes the fuse to blow C. Both A and B D. Neither A nor B

Neither A nor B

Two light bulbs are wired in series and one bulb burns out (opens.) Technician A says that the other bulb will work. Technician B says that the current will increase in the circuit because one electrical load (resistance) is no longer operating. Which technician is correct?

Neither Technician A nor B

High resistance in a circuit ________.

Reduces current flow through the circuit

Voltage supplied to a potentiometer may be called ________.

Reference voltage

Which variable resistor is most likely used for a dash light dimmer control?

Rheostat

If an insulated (power side) wire rubbed through a part of the insulation and the wire conductor touched the steel body of a vehicle, the type of failure would be called a(an) ________.

Short to ground

Which circuit is failure is most likely to cause a fuse to blow?

Short to ground

If two insulated wires were to melt together where the copper conductors touched each other, the type of failure would be called a(an) ________.

Short-to-voltage

Which of these elements has the least resistance?

Silver

The sum of the voltage drops in a series circuit equals the ________.

Source voltage

In a series circuit, total circuit resistance is equal to the ________ of the resistance of all loads in the circuit.

Sum

Which device produces electrical current resulting from heating of two dissimilar conductors?

Thermocouple

A potentiometer, a three-wire variable resistor, is used in which type of sensor?

Throttle Position (TP)

If one branch of a parallel circuit loses continuity, the other branches will still each receive source voltage and ground.

True

It is relatively easy to move an electron from the valence ring of a conductor.

True

A rheostat usually has how many wires?

Two

Which of these is also known as electrical potential?

Volts

Which of these describes electrical power?

Watts

Which of these automotive components does NOT rely on magnetism to operate correctly?

Wheel Bearing

The total circuit resistance of a parallel circuit is always ________ the lowest resistance present in any branch of the circuit.

less than

An electrical conductor is an element with ________ electrons in its outer orbit.

less than 4

If resistance is reduced in a series circuit, ________ current will flow.

more

The higher the resistance of a load in a series circuit, the ________ the voltage drop across that load.

more

In an incomplete circuit ________.

no current will flow

Creating electricity by exerting force on a crystal is called ________.

piezoelectricity

Which term describes electrical current resulting from pressure applied to certain crystals?

piezoelectricity

Like charges ________.

repel

Carbon and silicon are examples of ________.

semiconductors

A potentiometer usually has how many wires?

three

The outer electron shell is known as a(an) ________.

valence ring

The ________ is a unit of electrical pressure.

volt

Electromotive force is another term for ________.

voltage

Kirchhoff's law states that the voltage around a closed circuit is equal to the sum of ________ across all the loads.

voltage drops

How many watts are consumed by a light bulb if 1.2 amperes are measured when 12 volts are applied?

14.4 watts

How many watts are consumed by a starter motor if it draws 150 amperes at 10 volts?

1500

Calculate the total resistance and current in a 12 volt parallel circuit with three resistors of 4 ohms, 8 ohms, and 16 ohms, using any one of the five methods (calculator suggested). What is the total resistance and current?

2.3 ohms (5.3 ampere)

If 200 amperes flow from the positive terminal of a battery and operate the starter motor, how many amperes will flow back to the negative terminal of the battery?

200 amperes

An electrical load ________. A. May be an electrical device B. Has electrical resistance C. May be unwanted resistance caused by corrosion D. All of these

All of these

Technician A says that Ohm's law can be used to determine circuit current flow if total circuit resistance and total voltage are known. Technician B says that Ohm's law can be used to calculate the unknown resistance of a load in a circuit if total current and source voltage are known. Which technician is correct?

Both

Technician A says that electronic calculators have a memory function that can be used to calculate resistance, current, and voltage values for a parallel circuit. Technician B says to separate components of a series-parallel circuit to simplify calculations. Which technician is correct?

Both

A circuit with a short to power may cause ________. A. Improper operation of loads in the circuit B. Other circuits to malfunction C. Both A and B D. Neither A nor B

Both A and B

A circuit with excessive current flow ________. A. May create excess heat in conductors B. May cause a fuse to blow C. Both A and B D. Neither A nor B

Both A and B

A loose ground connection ________. A. Causes reduced current flow B. Causes less power to be available to the electrical components C. Both A and B D. Neither A nor B

Both A and B

Conductors that become too hot ________. A. Create excessive resistance B. Could be the result of a short to ground before the load C. Both A and B D. Neither A nor B

Both A and B

In a circuit with a short to ground ________. A. No current flows past the point of the short B. Some or all of the electrical loads may no longer work C. Both A and B D. Neither A nor B

Both A and B

In a series circuit ________. A. Current flow is constant at any point in the circuit B. Total circuit resistance is equal to the sum of all resistances in the circuit C. Both A and B D. Neither A nor B

Both A and B

Voltage drop is a better measurement of resistance than testing static resistance because ________. A. The resistance specification for the component is not required for diagnosis B. Current flow creates heat which adds to circuit resistance C. Both A and B D. Neither A nor B

Both A and B

Technician A says that the sum of the voltage drops in a series circuit should equal the source voltage. Technician B says the current (amperes) varies depending on the value of the resistance in a series circuit. Which technician is correct?

Both Technicians

Technician A says that a two-wire variable resistor is called a rheostat. Technician B says that a three-wire variable resistor is called a potentiometer. Which technician is correct?

Both technicians

Parallel circuits ________. A. Current flow through each branch of the circuit depends on the resistance present in that branch B. Have more than one path for current flow C. Both A and B D. Neither A nor B

C.

Excessive corrosion on an electrical connector ________.

Can cause lights to be dim

High resistance in a circuit can cause ________.

Clicking of relays Dim lights Slow Motor operation

The electrical path to ground may be completed by ________.

The vehicle frame or the metal body of the vehicle

Knowledge of parallel circuit fundamentals is necessary to diagnose ________. A. Diesel glow plug circuits B. Add-on lighting circuits C. Port fuel injection circuits D. All of these

D.

What is the symbol for voltage used in calculations?

E

In a circuit with high resistance ________.

Electrical loads may still operate but less efficiently

The current flowing into each junction of a parallel circuit ________ the current flow at the junction on the opposite end of that branch.

Equal

The voltage for each branch of a parallel circuit is ________.

Equal

A vehicle has four parking lights all connected in parallel and one of the bulbs burns out. Technician A says that this could cause the parking light fuse to blow (open). Technician B says that it would decrease the current in the circuit. Which technician is correct? Tech A Tech B Both Neither

Tech B

A series circuit has three resistors of 4 ohms each. The voltage drop across each resistor is 4 volts. Technician A says that the source voltage is 12 volts. Technician B says that the total resistance is 18 ohms. Which technician is correct?

Technician A only

A series circuit has two 10-ohm bulbs. A third 10-ohm bulb is added in series. Technician A says that the three bulbs will be dimmer than when only two bulbs were in the circuit. Technician B says that the current in the circuit will increase. Which technician is correct?

Technician A only

Technician A says that resistance increases as the diameter of a conductor increases. Technician B says that resistance increases as the temperature of a conductor increases. Which technician is correct?

Technician B only

Two bulbs are connected in parallel to a 12-volt battery. One bulb has a resistance of 6 ohms and the other bulb has a resistance of 2 ohms. Technician A says that only the 2-ohm bulb will light because all of the current will flow through the path with the least resistance and no current will flow through the 6-ohm bulb. Technician B says that the 6-ohm bulb will be dimmer than the 2-ohm bulb. Which technician is correct?

Technician B only

As temperature increases, ________.

The resistance of a conductor increases

The amperage in a series circuit is ________.

The same anywhere in the circuit

Which unit of electricity does the work in the circuit?

ampere

A complete circuit that is continuous from source through loads and back to ground has ________.

continuity

As additional branches are added to a a parallel circuit, total circuit resistance ________. Remains the same Decreases Increases None of the above

decreases

If a conductor is moved through a magnetic field ________ is produced.

electricity

What term describes the movement of electrons from one atom to another?

electricity

The automotive battery is based on the principle of ________.

electrochemistry

The sum of currents in each branch of a parallel circuit will ________ total circuit current.

equal

Semiconductors have how many electrons in their valence rings?

four

As additional branches are added to a parallel circuit, total circuit amperage ________.

increases

If the voltage increases in a circuit, what happens to the current (amperes) if the resistance stays the same?

increases

A positively charged atom is called a(n) ________.

ion