COMEDK20269 May 2026Evening ShiftPhysicsUnits and DimensionsActual
The dimensional formula for specific resistance is:
Options
- A[M ,L⁻³ ,T⁻² ,A⁻²]
- B[M ,L^3 ,T^3 ,A^2]
- C[M ,L^3 ,T⁻³ ,A⁻²]
- D[M ,L^3 ,T⁻³ ,A^2]
Correct answer
C. [M ,L^3 ,T⁻³ ,A⁻²]
Step-by-step solution
Specific resistance is given by = R A L . Resistance R = V I = W q I = W I^2 t . Dimensional formula of work W = [M L^2 T⁻²] . Dimensional formula of current I = [A] and time t = [T] . Dimensional formula of resistance R = [M L^2 T⁻²] [A^2 T] = [M L^2 T⁻³ A⁻²] . Dimensional formula of area A = [L^2] and length L = [L] . Dimensional formula of specific resistance = [M L^2 T⁻³ A⁻²] [L^2] [L] = [M L^3 T⁻³ A⁻²] . Answer: [M ,L^3 ,T⁻³ ,A⁻²]