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:
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:
E=mcΔTE=Pt

Pt=mcΔT

ΔT=Pt/mc

Doubling energy transfer rate will double the temperature rise. Halving the mass will also double the temperature rise. The change in temperature will be 4 times larger than the initial case, which is 40oC. This

gives the final temperature as 60oC.

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:

From the circuit symbols in the data booklet, component A is a heating element.

When current flows in the circuit, the heating element will increase in temperature and the resistance will increase. This will increase the total resistance of the circuit and result in a decrease in the current due to the relationship I=V/R.

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 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:
To calculate $n$, the student would rearrange the formula to get

• n=PV/RT

In both operations, the percentage uncertainty must be added, therefore the correct answer is C (2 % + 6 % + 1 % = 9 %)

Explanation:

• A. All electrical components are resistors to some extent. Even the best conductors will take up some amount of energy as electricity flows through them.
• B. While all materials are conducting given the appropriate voltage, at voltages as low as those shown on the graph, no current would flow if the material was not a good conductor of electricity.
• C. According to the graph, the ratio $V$/$I$ is not constant. By definition, that indicates a non-ohmic resistor. C is the correct answer.
• D. The voltage-current graph of an ohmic resistor is a straight line whose gradient represents a constant resistance.

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

The change of state will occur at the same temperature as the original graph but take less time to complete.

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:
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 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:

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.