In the diagram, zero of the vernier scale lies to the right of zero of main scale. So, it has positive zero error. N=0, Third division of vernier scale is coinciding with the main scale division. ∴ zero error =N+3×LeastCount=0+3×0.01 =0.03cm
So, zero correction =−0.3cm
That means, actual length will be 0.3cm less than the measured length.