Least count of screw gauge =500.5​=0.01 mm=ΔrDiameter, r=2.5 mm+20×500.5​=2.70 mmrΔr​=2.700.01​ or rΔr​×100=2.71​Now, density, d=Vm​=34​π(2r​)3m​Here, r is the diameter.∴dΔd​×​100={mΔm​+3(rΔr​)}×100=mΔm​×100+3×(rΔr​)×100=2%+3×2.71​=3.11%​