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Eddy Current Testing CMA 1
Q1. The coil in an eddy current probe is usually made from:
- Copper
- Aluminium
- Platinum
- Silver
Q2. The coil self inductance is:
- All of the other options are TRUE.
- Dependent on the coil’s wire length
- Dependent on the relative permeability of the core
- Dependent on its number of turns
Q3. Which of the following describes the voltage across a capacitor?
- The voltage is identical with the current through it
- The voltage lags the current through it by a phase of π/2 radians
- The voltage leads the current through it by a phase of π/2 radians
- The voltage is the inverse of the current through it
Q4. It was not until the end of the twentieth century that eddy current testing showed its true potential as a competitive testing method in the NDT market. This was because:
- All of the other options are TRUE
- Difficulty of the eddy current theory
- There was no general purpose, portable and user-friendly eddy current device
- Other NDT testing methods were available and preferred by professionals
Q5. Eddy currents are generated in a conductor by:
- Direct Current
- Voltage across the conductor
- The interaction of a time varying magnetic field with the conductor
- Resistance of the conductor
Q6. In measuring sinusoidal signals, devices would generally give more reliable measurements if they are set to measure:
- The peak to peak value.
- The root mean square value.
- The peak value.
- The DC offset.
Q7. In which of the following standards you can find information about equipment characteristics and verification in eddy current testing:
- EN 12668
- BS EN 13860
- BS EN 12084
- EN 14127
Q8. When a conductive but non-permeable material is brought in the proximity of a probe, the coil’s inductive reactance will:
- Decrease and then increase
- Decrease
- Remain the same
- Increase
Q9. A sinusoidal waveform has a period of 20 ms. Its frequency is:
- 5 Hz
- 50 Hz
- 500 Hz
- 5 kHz
Q10. In eddy current testing, the higher the frequency of the current used to drive the probe, the:
- More effective shielding will be needed due to skin effect
- Stronger the probe’s magnetic field will be
- Shallower the eddy currents will penetrate
- All of the other options are TRUE