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Sample Practice Test Questions
Voltage and current are __________ proportional.
directly
Voltage (V) is the electrical potential difference between two points. Electrons will flow as current from areas of high potential (concentration of electrons) to areas of low potential. Voltage and current are directly proportional in that the higher the voltage applied to a conductor the higher the current that will result.
The spark plugs fire a few extra degrees before top dead center when the engine is running faster. In this case the engine's timing is:
advanced
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.
The primary purpose of the muffler is to:
quiet exhaust
The muffler follows the catalytic converter and absorbs sound to help quiet load exhaust. It is followed by the exhaust pipe which is the final exit point for exhaust gas from the vehicle.
When using a hacksaw, blades with __________ teeth are more appropriate for cutting thinner materials.
more
A hacksaw has replaceable blades and is used to cut metal. The blade type is chosen based on the material that is to be cut. Blades with larger numbers of teeth per inch are more appropriate for cutting thinner materials.
Why does current in an electric circuit create heat?
heat is created when the current overcomes resistance in the wire
Current in an electric circuit creates heat when the current overcomes resistance in the wire.
Which of the following is not a primary function of a vehicle's lubrication system?
increases fuel economy
The lubrication system lubricates engine components by putting an oil film between them to reduce friction and smooth engine operation, cools by absorbing heat from engine parts, seals the pistons and cylinders to contain combustion, cleans contaminants, and quiets engine noise.
Water freezing or boiling is an example of which of the following?
phase transition
A substance undergoes a phase transition when it moves from one state of matter to another, for example, when water freezes or boils.
Which of the following does not filter air as part of the respiratory system?
epiglottis
After air enters through the nose, it passes through the nasal cavity which filters, moistens, and warms it. Further filtering takes place in the pharynx, which also helps protect against infection, and then in the trachea which is just past the epiglottis which prevents food from entering the airway.
The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber. This describes which engine stroke?
intake
The four-stroke piston cycle of internal combustion engines starts with the piston at top of the cylinder head (top dead center or TDC) during the intake stroke. The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber through the now open intake valve.