Question

DEFINE ISOTOPE, ISOBAR

Answer 1

Isotopes : Atoms with same number of protons but different number of neutrons are known as isotopes .
Isobars : Atoms with same atomic number but different mass number are known as isobars .

Answer 2

isotopes are elements having the same atomic number but different mass number
For example, carbon-12, carbon-13 and carbon-14 
isobars are elements having different atomic number but same mass number
For example, Manganese-56, Iron-56
 i hope it helps............