Q. Which two of the following five physical parameters have the same dimensions? (a) energy density (b) refractive index (c) dielectric constant (d) Young's modulus (e) magnetic field
A) (a) and (e)
B) (b) and (d)
C) (c) and (e)
D) (a) and (d)
Explanation
[Solution from source] Energy density is energy per unit volume, [ML²T⁻²]/[L³] = [ML⁻¹T⁻²], and Young's modulus is stress/strain, also [ML⁻¹T⁻²]. Refractive index and dielectric constant are both dimensionless, but the magnetic field [MT⁻²A⁻¹] matches neither of them. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.