Final answer:
Doubling the amplitude of a wave from 7 centimeters to 14 centimeters does not change its frequency; thus, the wave maintains its original frequency of 25 Hertz (Hz).
Step-by-step explanation:
The relationship between amplitude and frequency for a wave is not direct; changing the amplitude does not change the frequency. The two properties are independent in a linear medium. Therefore, if a certain wave has an amplitude of 7 centimeters (cm) and is then doubled to 14 cm, the frequency remains unchanged at 25 Hertz (Hz).
The frequency of a wave is determined by how often the waves pass a point in a given time period, typically measured in cycles per second (Hz), and is not affected by changes in amplitude. As such, the energy carried by the wave would increase due to the larger amplitude, but the frequency, or the number of times the wave cycles in one second, would stay the same.