Which of the following are even harmonic frequencies of a 2-MHz Tx?

To determine the even harmonic frequencies of a 2-MHz transducer, one needs to understand the concept of harmonics in ultrasound. Harmonics are integer multiples of a fundamental frequency; in this case, the fundamental frequency is 2 MHz.

The even harmonic frequencies can be calculated by multiplying the fundamental frequency by even integers (2, 4, 6, etc.). Therefore:

• The first even harmonic is 2 MHz × 2 = 4 MHz.
• The second even harmonic is 2 MHz × 4 = 8 MHz.
• The third even harmonic is 2 MHz × 6 = 12 MHz.

Thus, the even harmonics for a 2-MHz transducer include 4 MHz, 8 MHz, and 12 MHz. This makes the group of frequencies 4, 8, and 12 MHz the correct answer.

The other choices include frequencies that either feature odd harmonics, which are not considered even, or combinations that do not correctly reflect the multiples of the fundamental frequency. Understanding that even harmonics are strictly those produced by multiplying the fundamental frequency by even integers is key to navigating harmonic questions in sonography.