Explanation​:

The net change in the internal energy of a cyclic process is zero because it returns to its original temperature after each cycle. This means that statement I is correct.

The total change in entropy is zero for any reversible cycle. This means that statement II is correct as the gas returns to its original state each cycle.

The graph is for a heat engine, which takes in heat and does work on the environment. Therefore statement III is incorrect. A clockwise cycle always does net positive work on the environment.

Explanation​:
373$K$ is the boiling point of water. Temperature does not change until all water is boiled. B and C show temperature change at $t=0$. D is not compatible with the question. You might have seen graphs that resemble options B and D in this context, they are there to distract you.

Explanation​:

The kinetic model of ideal gases assumes that intermolecular forces (and therefore intermolecular potential energy) are negligible, and that the mean kinetic energy of molecules is directly proportional to gas temperature; hence, Properties I and II stay constant during the expansion. Conversely, Property III changes because gas pressure decreases during the expansion, and pressure scales with the frequency of molecular collisions with the walls of the piston.

Explanation​:
In an ideal gas system, it is assumed that molecules have negligible size and that there are no intermolecular forces. System A most resembles an ideal gas because it satisfies these criteria.

Whilst Systems B and C both contain molecules of significant size with strong intermolecular forces, System B is most likely to exhibit non-ideal gas characteristics due to the relatively high gas pressure, which corresponds to greater proximity between the molecules: a decreased intermolecular distance yields increased intermolecular forces, as well as enhancing the influence of non-negligible molecular size (the total molecular volume constitutes a greater percentage of the container volume).

Explanation​:
I.  Chemical energy in fossil fuel is transformed into thermal energy by burning and thermal energy is used to move (kinetic energy) steam that rotates the turbine and generator (also kinetic energy). Finally, electric energy is produced in generators.

II.  The kinetic energy of wind rotates the blades (kinetic energy) and rotates the generator. Finally, electric energy is produced in a generators.

III.  The gravitational potential energy of water behind a dam converts into kinetic energy as water falls down and rotates the turbine and generator. Finally, electric energy is produced in generators.

Explanation​:

The energy $E$ required to completely melt each substance is given by

• E=mL

where $m$ is the mass of the substance and $L$ is the specific latent heat of fusion.

Therefore, for a given power $P$, the duration tmelt​ of the plateau obeys the equation

tmelt=mL/P​

The two substances have equal values of $m$ and $P$, meaning that since Substance $A$ has a higher tmelt​ value than Substance $B$, it also possesses a higher $L$ value. Hence, Statement III is incorrect.

The rates of temperature change before and after melting are related to the specific heat capacity $c$ via the expression

• E = mcΔT
• PΔt=mcΔT
• ΔTΔt=Pmc​

The gradient of the graph is therefore inversely proportional to $c$.

In both solid and liquid state, Substance $A$ exhibits a higher value of ΔTΔt​ than Substance $B$, meaning that has a lower value of $c$. Hence, Statement I is correct.

Furthermore, for each substance, the gradient of the graph is lower in the liquid phase than in the solid phase, which means that after melting $c$ increases and Statement II is correct.

Explanation​:
The average kinetic energy doubles which means that the temperature doubles. To maintain constant pressure, volume would have to double.

Since the number of molecules also doubles, volume would have to double again to maintain constant pressure.

Thus the volume must get 4 times larger from pV=nRT

Explanation​:

Uranium-235 is a rare radioactive isotope on Earth, extracted from uranium ores. The available uranium is limited and will be depleted in time. Biomass will replenish in a human lifetime, so is considered renewable.

Explanation​:
Temperature appears to be doubled; but that is using the celsius scale. Absolute temperature is not doubled. So, $D$ is incorrect.

Volume cannot change, since the container's volume is fixed. The number of moles cannot change since the gas is enclosed in the container.

Hence, pressure is proportional to absolute temperature:

p2/p=[273+542]/[73+27] ⇒p2=1.09p

Explanation​:

Ice has half the specific heat capacity of liquid water and the rate of energy loss is constant. Therefore, after freezing the temperature of the system decreases at twice the rate compared to when cooling in the liquid state.

Explanation​:
Statement I is correct. The scattering of sunlight returns part of the sunlight back to space, reducing intensity on the ground.

Statement II is correct. The rotation of earth causes day and night, reducing the time the solar panel is exposed to sunlight and also changing the incident angle of sunlight on the panel.

Statement III is correct. The intensity on the solar panel is maximum when its surface is perpendicular to incident sunlight, but due to the seasons, the time of day and the installation angle of the panel the sunlight will not be normally incident on the panel.

Thus, D is the answer.

Explanation​:
Using V=W/q​ from the data booklet, we find that the charge q passing through the bulb in 2 seconds equals W/V=1000 J/200 V=5C.

Since I=Δq/Δt​, the current in the bulb is 5C/2 s=2.5 A

Explanation​:
The question gives $T$ in celsius. In kelvin, the temperature would be T+273.

Using the equation PV=nRT, we get number of moles = PV/RT. Since $M$ represents the number of moles, it will substitute into the equation for $n$ and $(T+273)$ will substitute as temperature in the equation giving

M=PV/R(T+273)​ which is answer A