Final answer:
If the negative terminal of a DMM is placed on the more positive section of a circuit while measuring voltage, the reading will have a minus sign. However, using ammeter mode by mistake while measuring voltage could lead to high current flow through the DMM, potentially resulting in a blown fuse or damage to the meter.
Step-by-step explanation:
When using a DMM (digital multimeter) to measure voltage, if you place the negative terminal on the more positive section of a circuit, the DMM display reading would show a minus symbol indicating that the polarity of the terminals is reversed. This will not damage the DMM or create a dead short, as the DMM is simply measuring potential difference between the two points.
If you were measuring voltage but accidentally put the meter in ammeter mode, this would be a problematic scenario. In ammeter mode, the DMM has a very low internal resistance. If it were to be connected across a source of voltage, there would be an almost nonexistent resistance to limit the current flow. This could lead to a very high current passing through the meter, which may cause the DMM's fuse to fail to protect its circuitry, or it could result in damage to the DMM itself if the internal fuse is not able to protect the meter properly.