Question

If the mass of a body is doubled, its density
1.Becomes two times
2.Becomes half
3.Does not change
4.Becomes 4 times
And give reasons.

Answer 1

density = mass/volume.

If mass is doubled by packing more closely the substance in the body, then the density becomes two times.

If mass is doubled by doubling the matter ie., adding an equal amount of matter then the density does not change.  (mass is doubled and volume is also doubled.)

Answer 2

density = mass/volume
density is directly proportional to mass.
So,if the mass is doubled,its density also doubled.It means becomes two times