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Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing, UT

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

Preparatory Notes for ASNT NDT Level III Examination - Ultrasonic Testing

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Q1-22 The beam spread half angle I the far field of a I” diameter transducer<br />

sending 5MHz longitudinal wave into Plexiglas block is?<br />

Answer: ϴ = Sin-1 (K λ/D) Assumed K=1.2 <strong>for</strong> null beam edge,<br />

ϴ = Sin -1 (K λ/D) =Sin-1(1.2V/DF)= Sin -1 [1.2x2730x10 3 / (25.4x5x10 6 )]<br />

=1.478°<br />

Q1-23 The near field of a round 1/2 “ diameter contact L-wave transducer<br />

being used on a steel test part operating at 3MHz is?<br />

Answer: Z= D2/4λ = 12.7 2 3x10 6 x / (4x5900x10 3 ) = 20.5mm

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