Automotive Engine Auxiliary Systems Questions and Answers – Battery Testing

This set of Automotive Engine Auxiliary Systems Multiple Choice Questions & Answers (MCQs) focuses on “Battery Testing”.

1. Which of the following part of a hydrometer which rises and is represented by an arrow below?
Find the part of hydrometer which rises & is represented by arrow in the figure
a) Rubber bulb
b) Float
c) Sampler tube
d) Glass body
View Answer

Answer: b
Explanation: 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
View Answer

Answer: d
Explanation: 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
View Answer

Answer: b
Explanation: 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.
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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
View Answer

Answer: b
Explanation: 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
View Answer

Answer: a
Explanation: 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.
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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
View Answer

Answer: c
Explanation: 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
View Answer

Answer: c
Explanation: A high discharge test is made for 10-15 min at the end of which the voltage should not fall below 1.5 volts and the difference of cell voltage of various cells should not exceed 0.2 volts and this test should be made only on fully charged or at least on half-fully charged batteries.
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8. Which of the following test does not use a voltmeter?
a) Open volt test
b) Cadmium test
c) High discharge test
d) Specific gravity test
View Answer

Answer: d
Explanation: Specific gravity test is the only test where a voltmeter is not used instead of a voltmeter a hydrometer is used to determine the specific gravity of the electrolyte. The float inside the hydrometer rises and then the read off the scale at the surface level of the sample drawn in.

9. What is the voltage value in the case of the positive terminal in a cadmium test?
a) Should not be less than 2.5
b) should be less than 1
c) Should be less than 0.5
d) Should not be less than 0.5
View Answer

Answer: a
Explanation: In a cadmium test the chemical condition of the positive and negative plate is found.In the case of a positive terminal, the voltage reading should not be less than 2.5 volts if the battery is nearing completion of its charge or 2.0 volts if the battery is being discharged at a normal rate.
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10. What is the value of the specific gravity of a fully charged battery?
a) 1
b) 1.29
c) 0.5
d) 1.1
View Answer

Answer: b
Explanation: The specific gravity in many cases is used to find the state of the battery. The specific gravity for a fully charged battery is 1.29 and along with this reading the temperature is also noted accordingly and then compared with the chart supplied by the battery manufacturer.

11. What is the value of the specific gravity of a fully discharged battery?
a) 0.1
b) 1.1
c) 0.5
d) 0
View Answer

Answer: b
Explanation: The specific gravity is used to find the state of the battery. When the battery has completely discharged the value of the specific gravity reaches a value of 1.1 after which the battery has to be jump-started or replaced if the plates are damaged.

12. What is the value in volts of the negative terminal in the case of the cadmium test?
a) Not more than 0.2
b) more than 0.5
c) Not more than 1
d) More than 1.3
View Answer

Answer: a
Explanation: In a cadmium test the chemical condition of the positive and negative plates is determined. The reading with the negative battery terminal should not be more than 0.2 volts when the battery is being discharged at a normal rate. A higher reading in this case will indicate defects in negative plates.

13. Which of the following is not a part of the hydrometer apparatus?
a) Ebonite tube
b) Sampler tube
c) Rubber bulb
d) Float
View Answer

Answer: a
Explanation: 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. Whereas the ebonite tube in use encloses the cadmium rod in the cadmium test.

Sanfoundry Global Education & Learning Series – Automotive Engine Auxiliary Systems.

To practice all areas of Automotive Engine Auxiliary Systems, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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