Question

1. a changed value component in an rl parallel circuit

measures 0 volts across it
causes current to stop
measures the applied voltage across it
increases or decreases the opposition to current

Explanation:

In an RL parallel circuit, the voltage across each parallel branch (including the component with changed value) is equal to the applied voltage (due to the property of parallel circuits: \(V = V_R=V_L\)).

• Option a: Incorrect. Only if the component is short - circuited (which is not the case of a "changed value" in general) would the voltage across it be 0.
• Option b: Incorrect. In a parallel circuit, even if one branch has a changed component value (as long as it is not an open - circuit), current will still flow through other branches.
• Option d: Incorrect. In a parallel RL circuit, the opposition to current (impedance \(Z=\frac{1}{\sqrt{\frac{1}{R^{2}}+\frac{1}{X_{L}^{2}}}}\)) is a function of both \(R\) and \(X_L\). A change in one component (say \(R\) or \(X_L\)) does not just "increase or decrease the opposition to current" in a simple additive or subtractive sense as described in this option.

Answer:

C. measures the applied voltage across it