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Sample Practice Test Questions
Use Ohm's Law to calculate the value of voltage in this circuit if resistance is 10 Ω and current is 2.5 amps.
Ohm's law specifies the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit: V = IR.
V = \( I \times R \) = \( 2.5 \times 10 \) = 25 V
Which type of screwdriver has a straight slot in the top?
slotted
Screwdrivers come in many different handle, shaft, and tip configurations for use in a wide variety of applications. Screwdrivers are classified by their tip which is shaped to fit a corresponding screw head. Common tips are slotted (flat) and Phillips (x-shaped).
Which of the following is a common firing order for four-cylinder engines?
1-3-4-2
The stroke cycle of an engine is governed by the crankshaft which serves to regulate the firing order of the cylinders. All cylinders are not on the same stroke at the same time and correct firing order is important to balance engine operation and minimize vibrations. A common firing order for four-cylinder engines is 1-3-4-2 which indicates that cylinders 1 and 3 fire (power stroke)together and cylinders 4 and 2 fire together.
Ignition timing is measured in number of degrees:
before top dead center
Ignition timing defines the point in time at the end of the compression stroke that the spark plug fires. Measured in number of degrees before top dead center (BTDC), the exact point that the spark plugs initiate combustion varies depending on the speed of the engine. The timing is advanced (the spark plugs fire a few more degrees BTDC) when the engine is running faster and retarded when it's running slower.
A capacitor is often used for which of the following purposes?
to maintain power in a circuit when the primary power source is disconnected
Capacitors store electricity and are used in circuits as temporary batteries. Capacitors are charged by DC current (AC current passes through a capacitor) and that stored charge can later be dissipated into the circuit as needed. Capacitors are often used to maintain power within a system when it is disconnected from its primary power source or to smooth out or filter voltage within a circuit.
The ignition coil is a(n):
step-up transformer
The ignition coil steps up the 12 volts available from the battery or alternator to a voltage of 30,000 or more volts at the spark plug. Converting a lower voltage input into a higher voltage output makes the ignition coil a step-up transformer.
Which of the following substances gives up negatively charged hydroxide ions (OH-) when dissolved in water?
base
An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.
Which is the proper order of Earth's atmospheric layers from the surface up to space?
troposphere, stratosphere, mesosphere, thermosphere
The troposphere is the closest layer to Earth, followed by the stratosphere, mesosphere, and finally the thermosphere which borders space.