Q&A Forum
1131 questions found
When an open pipe is played and a note is heard
- the lowest frequency of the note is called second harmonic.
- resonance occurs with standing waves set up inside the pipe.
- the fundamental frequency is always twice the pipe diameter.
please explain.
A good refrigerant has
- high condensing pressure, low evaporating temperature.
- high condensing pressure, high vaporating temperature.
- low condensing pressure, low vaporating temperature.
will you please explain the reason??
The length of a resonant antenna dipole is
- lambda
- lambda/2
- lambda/4
Q897) The length of a resonant antenna dipole is -lambda/2
Q955) The length of a resonant antenna dipole is -Lambda/4
There can only be one answer? I think - Lambda/4
Any ideas?
Medium vibration of 4 to 6 times per revolution is experienced on a helicopter. The primary control method is
- inspect main rotor head and main drive shaft
- design of engine and gearbox supports
- inspect loose fixtures and fittings
I selected
-Design of engine and gearbox supports
Medium and High frequency Vibrations – Depending on the helicopter the source may be engine and transmission cooling fan and accessories such as air conditioner compressors, or driveline components.
Any ideas?
A circuit has a resistance of 50 ohms and an inductance of 0.2 Henry. If it is connected to a 200 volt 50 Hz supply the reactance will be
- 6.284 ohms.
- 62.84 ohms.
- 31.42 ohms.
help ?