Explanation​:

The temperature of the solid is 373 $K$ (100 + 273) after the reaction takes place, so a temperature change of $(373-50)=323K$ is required to achieve the target temperature.

The energy $E$ needed for this change is related to the temperature change $\Delta T$ by the expression

E=mcΔT=323mc

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​:

Solar constant (S) is the intensity of sun light at the orbit of the planet. For Earth, at a distance of 1AU from the sun, it is 1.36×10^3 W m^−2

Intensity is inversely proportional to the square of the distance from the source: I∝1/d^2

$\therefore$ Intensity at a distance 30 times as far will be 30^2 (=900) times weaker.

SNeptune=1360/900=1.5 W m^−2

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​:
Average kinetic energy increases as the temperature increases and stays constant during the vapourisation process. Moreover, average kinetic energy is zero at absolute zero (−273oC) temperature, which is not the case for water (0−100oC)

Explanation​:
Non-renewable sources are sources where the rate of replenishment is much longer than a human lifespan. Examples include nuclear, coal, oil, and natural gas. Therefore, the answer is A.

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​:
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​:

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​:

Once the switch is closed, the heating element in the circuit on the left  increases in temperature.

This increase affects the thermistor by decreasing its resistance. As a result the current in the circuit on the right increases, causing the lamp's brightness to increase.

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

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​:
Uranium is a non-renewable source of energy whereas wind is renewable.