What two ways could a dip meter be used in an amateur station?

A dip meter (or grid-dip oscillator) is an instrument that contains a tunable RF oscillator. When its external coil is brought near a de-energized tuned circuit or an antenna trap, the circuit absorbs energy from the meter if their resonant frequencies match. This absorption causes a noticeable dip in the meter's current reading. Because its primary function relies on this LC resonance absorption, it is perfectly suited for checking the resonant frequency of passive tuned circuits and antenna traps. It essentially acts as a localized, variable RF source to find where a circuit naturally resonates. The other options are incorrect because a dip meter cannot measure percentage modulation (which requires an oscilloscope or modulation monitor) nor can it measure impedance directly (which requires an impedance bridge or an antenna analyzer).