Automotive Engine Auxiliary Systems Multiple Choice Questions on “Battery Testing”.
1. Which of the following part of a hydrometer which rises and is represented by an arrow below?
a) Rubber bulb
b) Float
c) Sampler tube
d) Glass body
Answer: b
Clarification: The hydrometer is in the form of a glass tubular body with a rubber bulb at the top and a sampler tube at the bottom. There is a glass float inside the glass body. This float has a vertical density scale which when dipped in the electrolyte rises and shown a read off the scale on the surface level of the sample drawn in.
2. Which of the following device is used in the specific gravity test?
a) Cadmium rod
b) Voltmeter
c) Cell voltage tester
d) Hydrometer
Answer: d
Clarification: The battery is filled with electrolyte. The specific gravity test is conducted with the help of a hydrometer. The hydrometer is in the form of a glass tubular body with a rubber bulb at the top and a sampler tube at the bottom. There is a glass float inside the glass body.
3. Which of the following meter is used in the open volt test?
a) Ammeter
b) Voltmeter
c) Galvanometer
d) Hydrometer
Answer: b
Clarification: In the open volt test the state of charge is determined. The open-circuit voltage of a battery cell is measured with the help of an ordinary voltmeter. The open-circuit voltage of a fully charged battery cell is about 2.1 volts.
4. Which of the following test helps in the determination of the chemical condition of positive and negative plates of a battery?
a) Specific gravity test
b) Cadmium test
c) Open volt test
d) High discharge test
Answer: b
Clarification: The cadmium test is conducted to know the chemical condition of the positive and negative plates and is performed only when the battery is either on charge or discharge. In the case of the positive terminal the voltage reading should not be less than 2.5 volts and in case of the negative battery,the terminal should not be more than 0.2 volts.
5. Which of the following is the correct relationship between the voltage of a cell and specific gravity in an open volt test?
a) The voltage of cell=Specific gravity +.840
b) The voltage of cell=Specific gravity -.840
c) Specific gravity =voltage of the cell +12
d) Specific gravity =voltage of the cell -12
Answer: a
Clarification: In an open volt test a change of 0.01 volt of open-circuit voltage is equivalent to a change of 0.010 in the specific gravity of the electrolyte. The relationship between the open-circuit voltage of a battery and its specific gravity is Voltage of the cell =specific gravity +.840.
6. What is the test duration in seconds of a high discharge test when exceeding the time may lead to permanent damage?
a) 5
b) 10
c) 15
d) 20
Answer: c
Clarification: A high discharge test is conducted with the help of a cell voltage tester wherein the voltmeter is connected to two legs with a high resistance placed across them. This test should not be made continuously for more than 15 seconds otherwise the battery plates will get permanently damaged.
7. What is the correct state of the battery during which a high discharge test must be performed?
a) Low load condition
b) Heavy load condition
c) Fully charged state
d) Fully discharge state