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Question

Physics Question on Units and measurement

Given below are two statements:
Statement (I): Dimensions of specific heat is [L2T2K1][L^{2}T^{-2}K^{-1}]
Statement (II): Dimensions of gas constant is [ML2T2K1][M L^{2}T^{-2}K^{-1}]

A

Statement (I) is incorrect but statement (II) is correct

B

Both statement (I) and statement (II) are incorrect

C

Statement (I) is correct but statement (II) is incorrect

D

Both statement (I) and statement (II) are correct

Answer

Statement (I) is correct but statement (II) is incorrect

Explanation

Solution

ΔQ=mSΔT\Delta Q = m S \Delta T
s=ΔQmΔTs = \frac{\Delta Q}{m \Delta T}
[s]=[ML2T2]MK[s] = \frac{\left[ M L^2 T^{-2} \right]}{M \cdot K}
[s]=[L2T2K1][s] = \left[ L^2 T^{-2} K^{-1} \right]
Statement-(I) is correct.
From PV=nRTPV = nRT, we have:
R=PVnTR = \frac{PV}{nT}
Substitute dimensions:
[R]=[ML1T2L3][mol][K][R] = \frac{\left[ M L^{-1} T^{-2} L^3 \right]}{\left[ \text{mol} \right] \cdot \left[ K \right]}
Simplify:
[R]=[ML2T2mol1K1][R] = \left[ M L^2 T^{-2} \text{mol}^{-1} K^{-1} \right]
Statement-(II) is incorrect.