Physics

At a given temperature, the average kinetic energy of gas molecules is the same for all gases regardless of their type. This is because temperature is directly proportional to the average kinetic energy of the molecules.

For diatomic gases, the ratio of specific heats (γ) is approximately 1.4 under normal conditions, reflecting their degrees of freedom. This value is standard in thermodynamics for diatomic molecules like oxygen and nitrogen.

Increasing pressure raises the boiling point of a substance because higher pressure requires the substance's vapor pressure to be higher to boil, thus increasing the temperature at which boiling occurs.

In adiabatic compression, work is done on the system without heat exchange, causing the internal energy to increase. In contrast, adiabatic expansion decreases internal energy, and isothermal processes keep internal energy constant.

The gravitational acceleration on the Moon's surface is approximately 1.62 m/s², which is much less than Earth's 9.8 m/s². This value corresponds to option B.

Potential energy is the energy stored in an object due to its position or configuration, such as height above the ground. This distinguishes it from kinetic energy, which is due to motion.

A flywheel smooths out the energy variations in an engine by storing rotational energy, and its added weight helps stabilize the engine's operation. Therefore, both A and B are correct purposes of a flywheel.

The emf (E) induced in a self-inductance L is given by E = L * (dI/dt). Here, dI = 2 A - 3 A = -1 A, dt = 1 ms = 0.001 s, so dI/dt = -1000 A/s. Taking magnitude, L = E / |dI/dt| = 5 V / 1000 A/s = 0.005 H = 5 mH.

The efficiency of a Carnot engine is given by the formula η = 1 - (T_cold / T_hot), where temperatures must be in Kelvin. Converting 150°C and 50°C to Kelvin gives 423 K and 323 K respectively. Substituting these values, efficiency = 1 - (323/423) ≈ 0.235 or 23.5%, which rounds to 23.6%. Therefore, the correct answer is option C (23.6%). The original answer D (29.4%) is incorrect based on the calculation and standard thermodynamics principles.

Moderators in nuclear reactors slow down fast neutrons to thermal energies, increasing the likelihood of fission. They do not bring neutrons to rest, absorb them, or reflect them primarily.