Physics · UNITS AND MEASUREMENT

The dimensional formula of thermal conductivity \( k \) in the heat flow equation \( Q = \frac{k A (T_1 - T_2) t}{d} \) is:

1. A
   \( [\text{M L T}^{-3} \text{K}^{-1}] \)
2. B
   \( [\text{M L}^2 \text{T}^{-3} \text{K}^{-1}] \)
3. C
   \( [\text{M L T}^{-2} \text{K}^{-1}] \)
4. D
   \( [\text{M L}^2 \text{T}^{-2} \text{K}^{-1}] \)