Which two of the following five physical parameters have the same dimensions?1. energy density             2. Refractive index          3. Dielectric constant      4. Young’s modulus         5.magnetic field

(1)  Energy density = EnergyVolume   =  ML2T−2L3 = ML−1T−2(2) Refractive index has no dimensions(3) Dielectric constant has no dimensions.(4) Young’s modulus.Y = FlAΔl = MLT−2LL2L = ML−1T−2(5) Magnetic field,B = FII = MLT−2AL = MT−2A−1Therefore, option (c) is correct.