Atransmission system at a radio station uses a/an to convert a direct current into a high frequency alternating current.
a. oscillator
b. modulator
c. transmitting antenna
d. demodulator
user: a unit for measuring frequency is the
a. ampere.
b. hertz.
c. ohm.
d. watt.

A transmission system at a radio station uses an oscillator to convert a direct current into a high frequency alternating current. Direct current or DC is the current in which the flow of the charge is one directional. In case of alternating current or AC, the flow of the charge reverses direction after a period of time.
In regards to the second question, a unit for measuring frequency is the hertz. So the correct answer to the given question is option “B”.

Answer (d) the universe had cooled enough for atoms to combine, protons and neutrons were too far apart to form nuclei;