If the resistance of an electric circuit is 12 ohms and the voltage in the circuit is 60 v, the current flowing through the circuit is
a. 60
a. b. 5
a. c. 0.2
a. d. 720
a. user: a transmission system at a radio station uses a/an to convert a direct current into a high frequency alternating current.
a. modulator
b. transmitting antenna
c. oscillator
d. demodulator user: when all parts of a circuit are composed of conducting materials, the circuit is said to be
a.

Question 2. 

A transmission system at a radio station consists of essentially the following devices:

1. An oscillator, which converts a direct current into a high-frequency alternating current.

2. A transmitting antenna, which sends out radio waves having the same frequency as the current supplied by the oscillator.

3. A microphone, which picks up the sound waves and converts them into a suitable electric current with the same pattern as the sound waves.

4. A modulator, which enables the waves produced by the antenna to “carry” the pattern of the sound waves picked up by the microphone.

The answer is C. Oscillator

when it gains or loses electrons