In a day the heart pumps 7500 L of blood of density 1.05×10³ kg/m³, doing work equivalent to lifting it through 1.63 m. If power is 148/10ⁿ W, find n.
Physics · Mixed Chapter
JEE Main Practice

Question

In a day the heart pumps 7500 L of blood of density 1.05×10³ kg/m³, doing work equivalent to lifting it through 1.63 m. If power is 148/10ⁿ W, find n.

G1 Physics · Accepted Answer

Step 1: Blood volume =7.5 m³ and mass =1.05×10³×7.5 =7875 kg. Step 2: Work in one day W =mgh≈7875×9.8×1.63 ≈1.258×10⁵ J. Step 3: Divide by 86,400 s: P≈1.46 W (≈1.48 W using rounded constants). Step 4: 148/10²=1.48 W, so the source intends n=2.