The transmission system at a radio station uses a/an to convert s direct current into a high frequency alternating current.

The transmission system at a radio station uses an oscillator to convert direct current into a high frequency alternating current.

Answer

Oscillator

Reason

Oscillators is a circuit  that changes  direct current from to alternating current (AC) signal.

Oscillator often produces  periodic, oscillating electronic signal, a sine wave or a square wave.

Therefore an oscillator is used to convert direct current into a high frequency alternating current.

pecialized keyboards

you get 2.3=1.21*\frac{a}2 or 4.6=1.21a or a=3.802 (b)

explanation: