The correct answer to the question is X- rays i.e the electromagnetic wave which has frequency that is higher than ultra violet wave and smaller than gamma ray is X-ray.
EXPLANATION:
As per the electromagnetic spectrum of waves, gamma ray has the least wavelength i.e it has the maximum frequency. The minimum frequency that is possessed by electromagnetic wave is radio wave.
If we arrange all the electromagnetic radiations in ascending order of frequency, the perfect order will be -
Radio wave < Micro wave < Infrared wave < Visible light < U.V ray < X - ray < Gamma ray.
From the electromagnetic spectrum, it is obvious that X -rays lie between gamma ray and U.V ray . Its frequency is smaller than gamma ray but higher than ultra violet wave.
