Ultrasonic waves produced in a medium can be detected by
A. Kundt’s tube
B. Quincke’s Method
C. A Telephone
D. Hebb’s method

Hint: The ultrasonic waves have a frequency higher than that of the audible. The ultrasonic detectors are used to measure the distance of the target objects by sending waves. Ultrasonic waves are also called the inaudible. The methods used to detect the ultrasonic waves should be known to solve this problem.

Complete step by step answer:
With the help of Kundt's tube, the ultrasonic waves can be detected. In the form of heaps, the lycopodium powder gets collected at the nodes. Half the value of the wavelength of the waves equals the average distance between the adjacent heaps. If the wavelength of the ultrasonic waves is in terms of a few mm, then, this method cannot be used.
In the form of an aqueous solution or a liquid, the magnetic susceptibility of a paramagnetic substance can be determined using Quincke's Method. In a non-uniform magnetic field, the force experienced by a magnetized material is used in this method. Thus, Quincke's method cannot be used to detect the ultrasonic waves produced in a medium.
The method that can be used to determine the process of altering the weights between the model neurons, is Hebb's principle. In the case of neurons, the weight increases if they activate simultaneously, similarly, the weight decreases if they activate separately. Thus, Hebb’s principle method cannot be used to detect the ultrasonic waves produced in a medium.
The other methods to detect ultrasonic waves are the Sensitive flame method, Thermal detectors and Quartz crystal method.

So, the correct answer is “Option A”.

Note: In the explanation method, the other methods are explained as well for additional information purpose. The other methods to detect ultrasonic waves are the Sensitive flame method, Thermal detectors and Quartz crystal method.