10.9×10⁵/m
11.9×10⁵/m
10.9×10⁴/m
10.9×10³/m
Correct option is B. 10.9×10⁵/mR.P.=2μsinθ1.22λμ=1tanθ≈sinθ=a/f=1/5=0.2⇒R.D.=2×1×0.2/(1.22×6×10⁻⁷)=4×10⁶/3.66RP.=10.9×10⁵/m.