An electromagnetic wave is found to have a wavelength of the order...

The wavelength of $1\text{ \AA}$ ($10^{-10}\text{ m}$) falls in the characteristic range of X-rays, which typically span from $10^{-8}\text{ m}$ to $10^{-13}\text{ m}$.

According to the electromagnetic spectrum, X-rays are commonly produced by bombarding a metal target with high energy electrons.

Gamma rays generally have even shorter wavelengths and are of nuclear origin. Ultraviolet rays have longer wavelengths ($10^{-8}\text{ m}$ to $4 \times 10^{-7}\text{ m}$). The vibration of atoms and molecules produces infrared waves, not X-rays.

Answer: X-rays; produced by bombarding a metal target with high energy electrons.