Carnot efficiency η = 1 - T₂/T₁. If T₁=600K, T₂=300K, η is: MCQ with Answer and Explanation

Explanation:
1 J = 1 kg m²/s². In CGS, 1 kg = 10³ g, 1 m = 10² cm => 1 J = (10³ g) × (10² cm)² / s² = 10⁷ g cm²/s² = 10⁷ erg. Key conversion.

Explanation:
Total distance = 200 m (forward) + 100 m (back) = 300 m. Total time = 20 s + 10 s = 30 s. Average speed = total distance / total time = 300/30 = 10 m/s. Average velocity would be displacement (200-100=100 m) / 30 s = 3.33 m/s. But average speed is 10 m/s. Wait, 300/30 = 10. But that's option A 10 m/s. I need to check: Did I compute right? 200 m forward, then returns 100 m back, so total path length = 300 m. Time total = 30 s. Average speed = 10 m/s. Option A is 10 m/s, B is 6.67. That gives A. But to test concept, many confuse with velocity. I'll set correct answer A. But I'll adjust to make distinction: Maybe distance first 200 m at 10 m/s, return 100 m at 5 m/s? Already given times. So correct answer A. It's moderate. I'll keep.

Explanation:
Magnetic field intensity (H) and magnetic field (B) are vectors. Magnetic flux is scalar (Φ = B·A). Resistance scalar, potential scalar. Vector quantities have direction. Current has direction but adds by scalar law, considered tensor sometimes but in basic physics not vector.