Temperature of low pressure

The temperature of low pressure hydrogen is reduced from 100°C to 20°C. The rms speed of its molecules decreases by approximately:a. 80%b. 89%c. 46%d. 21%e. 11%12.Which, of the following temperature changes, would show the smallest change in entropy for a pan of water on a hot plate?1. 20°C to 30°C2. 30°C to 40°C3. 40°C to 45°C4. 80°C to 85°Ca. 1b. 1 and 2 are tied for smallest ?Sc. 2d. 3e. 413.The temperatures TC of the cold reservoirs and the temperatures TH of the hot reservoirs for four Carnot heat engines areengine 1: TC = 400K and TH = 500Kengine 2: TC = 500K and TH = 600Kengine 3: TC = 400K and TH = 600Kengine 4: TC = 600K and TH = 800KRank these engines according to their efficiencies, least to greatest.a. 1, 2, 3, 4b. 1 and 2 tie, then 3 and 4 tiec. 2, 1, 3, 4d. 1, 2, 4, 3e. 2, 1, 4, 314.An object hangs from a spring balance. The balance indicates 30N in air and 20N when the object is submerged in water. What does the balance indicate when the object is submersed in a liquid with a density that is half that of water?a. 20Nb. 25Nc. 30Nd. 35Ne. 40N15.Water flows through a cylindrical pipe of varying cross section. The velocity is 3.0m/s at a point where the pipe diameter is 1.0 cm. At a point where the pipe diameter is 3.0 cm, the velocity is:a. 9m/sb. 3m/sc. 1m/sd. 0.33m/se. 0.11m/s