Answer:
Option C
Explanation:
Least count of screw gauage= 0.550
=0.01 mm=△r
Diameter , r=2.5mm+20×0.550
=270mm
△rr=0.012.70
or △rr×100=12.7
now, density d=mV=m43π(r2)3
Here r is the diameter
∴ △dd×100={△mm+3(△rr)}×100
=△mm×100+3×(△rr)×100
=2%+3×127=3.11%