Q. There metal walls of same cross-sectional area having thermal conductivity in the ratio 1 : 2 : 4 transfer heat at the rate of 15000 kcal/hr. For same thickness of wall, the temperature deop will be in the ratio

• (A) 1 ; 2 ; 4
• (B) 1 : D. 4 ; 2 ; 1 E. 1 ; 1 ; 1
• (C) ---
• (D) ---