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? Question 31 options: Cannot be determined 200 amperes About one-half (100 amperes) Zero A braided wire running from the negative battery terminal to the body of a vehicle is known as a ground strap. Question 32 options: facilitating circuit redundant source ground strap None of these In a schematic, a wire is labeled “0.8 BLK/WHT.” This wire is white with a black stripe. Question 33 options: 0.8 mm square diameter white with a black stripe Both 0.8 mm square diameter and black with a white stripe Neither 0.8 mm diameter nor white with a black stripe A PTC circuit protector prevents excessive current flow in a circuit by changing to a very high resistance. Question 34 options: burning open opening a set of contacts grounding the current changing to a very high resistance What is the total resistance of this circuit? Question 35 options: Not enough information 3 ohms 36 ohms 4 ohms
The Correct Answer and Explanation is:
Question 31:
Correct Answer: 200 amperes
Explanation:
In any electrical circuit, especially a closed-loop DC system like that of an automobile, the current that leaves the battery must return to it. If 200 amperes are flowing from the positive terminal to the starter motor, then 200 amperes must return to the negative terminal to complete the circuit. This principle is based on the law of conservation of charge and Kirchhoff’s Current Law, which states that the current entering any junction must equal the current leaving. The current doesn’t get “used up”; instead, energy is transferred from electrical to mechanical (by the motor), but the current still flows back. Hence, 200 amperes flow back to the battery’s negative terminal.
Question 32:
Correct Answer: ground strap
Explanation:
The braided wire connecting the negative terminal of a battery to the vehicle’s body is known as a ground strap. This ensures the entire metal body of the vehicle acts as a common ground or return path for electrical current. Ground straps are critical for completing circuits and minimizing resistance. They also help protect the vehicle’s electronics by ensuring a stable reference potential and reducing electromagnetic interference.
Question 33:
Correct Answer: 0.8 mm square diameter and black with a white stripe
Explanation:
In wiring schematics, “0.8 BLK/WHT” means:
- 0.8 mm² refers to the cross-sectional area of the wire, not diameter.
- BLK/WHT means the wire is black with a white stripe.
So, the wire has a cross-sectional area of 0.8 mm² and is black with a white stripe, making this the correct interpretation.
Question 34:
Correct Answer: changing to a very high resistance
Explanation:
A PTC (Positive Temperature Coefficient) circuit protector works by increasing its resistance as temperature (from current) rises. It doesn’t “burn out” like a fuse. When the current exceeds safe levels, the PTC material heats up, causing resistance to increase rapidly, reducing current flow. Once the circuit cools, the PTC resets and allows normal operation again. It’s a self-resetting circuit protector.
Question 35:
Correct Answer: Not enough information
Explanation:
This question asks for total resistance in a circuit, but no diagram, values, or configuration (series or parallel) are provided. Resistance in a circuit depends on how resistors are arranged. Without knowing the number of resistors, their values, or the layout, it’s impossible to calculate the total resistance. Therefore, the only correct answer is “Not enough information”.
Summary:
- Q31: 200 amperes
- Q32: ground strap
- Q33: 0.8 mm² and black with white stripe
- Q34: changing to a very high resistance
- Q35: Not enough information
