Final answer:
The resistance of the combination is 11.522 Ω. The percent decrease in current can be calculated using Ohm's Law and is significant. The percent increase in voltage can also be calculated using Ohm's Law and is significant.
Step-by-step explanation:
To calculate the resistance of the combination, we need to add the resistance of the ammeter and the resistor together. So, the resistance of the combination would be 0.022 Ω + 11.5 Ω = 11.522 Ω.
To calculate the percent decrease in current, we can use Ohm's Law. Ohm's Law states that the current in a circuit is equal to the voltage divided by the resistance. Since the voltage is kept the same across the combination, the current can be calculated by dividing the voltage by the resistance of the combination. The percentage decrease in current can be calculated by subtracting the current through the combination from the current through the resistor alone, and then dividing that by the current through the resistor alone and multiplying by 100.
To calculate the percent increase in voltage, we can use Ohm's Law again. This time, since the current is kept the same through the combination, the voltage can be calculated by multiplying the current by the resistance of the combination. The percentage increase in voltage can be calculated by subtracting the voltage across the combination from the voltage across the resistor alone, and then dividing that by the voltage across the resistor alone and multiplying by 100.
The changes found in parts (c) and (d) are significant because they represent the impact of adding an ammeter to the circuit, which can affect the current and voltage measurements in the circuit.