Which of the following produces a shorter wavelength?

The selection of Cobalt-60 as producing a shorter wavelength is based on its specific properties as a radioactive isotope. Cobalt-60 is known for emitting gamma radiation, which has very short wavelengths compared to the radiation produced by other options listed. Gamma radiation is at the high-energy end of the electromagnetic spectrum, making it one of the highest frequency forms of electromagnetic radiation.

Cobalt-60 undergoes beta decay to transform into Nickel-60 and emits gamma rays as part of this process. The energy of the emitted gamma photons is high, corresponding to shorter wavelengths that range approximately from 1 to 0.01 nanometers. This characteristic makes Cobalt-60 particularly useful in applications such as cancer treatment and industrial radiography, where penetrating power and high energy are essential.

In contrast, the other isotopes listed generally emit radiation in forms or energies that correlate with longer wavelengths, such as beta particles or lower-energy gamma radiation, which results in longer wavelengths. Therefore, Cobalt-60 is identified as the source that produces shorter wavelengths among the options provided.