An ion with a mass m and a magnitude of charge of 1e is initially at rest when it is accelerated by a potential difference of magnitude ΔV. After exiting the accelerating potential, it enters a region with a uniform magnetic field perpendicular to the ion's velocity. The ion moves in a semicircle of radius R. Next, an ion with a mass m' and a magnitude of charge of 2e is accelerated by the same potential difference and deflected by the same magnetic field. The radius of its semicircular path is R' = 4R. Find the ratio of the ion masses, m'/m.

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

In a system, when potential energy decreases, then entropy also decreases. true false

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.