Answer:
Wavelength, 
Explanation:
We have,
Velocity of the object, 
Mass of the object, 
It is required to find the wavelength of the object. The relation between wavelength and velocity of the object is given by :

h is Planck's constant

So, the wavelength of the object is
.
Please list your question in the comments.
The first one is the answer
isotopes of an atom have different number of neutrons . the number of protons are not different in isotopes of an atom