Are isotopes that emit radiation because they have unstable nuclei.
a. gamma rays
b. radioisotopes
c. radioactivity
d. nuclear radiation

The correct answer among the choices given is option B. Radioisotopes are isotopes that emit radiation because they have unstable nuclei. These are radioactive isotopes of an element. They are defined as atoms that contain an unstable combination of neutrons and protons.

1.0177 g/cm³

Explanation:

We are given;

Mass of the cube = 40 grams Length of the cube = 3.4 units

We are required to get the density of the cube;

Assuming the length is 3.4 cmThe volume of the cube is given by l³

Thus, Volume of the cube = 3.4 cm × 3.4 cm × 3.4 cm

                                 = 39.304 cm³

But, density = Mass ÷ volume

                    = 40 g ÷ 39.304 cm³

                    = 1.0177 g/cm³

Therefore, the density of the cube is 1.0177 g/cm³