Solar radiation is in6x;o9b8 dw; qqifdm q0cident on a planet, whose surface absorbs 65% of incident intensity. What iqim o6b; qxdf 90;d8wqs the albedo of the planet?

  The orders of energy transformations in three power sta o4d 30lk(htymuw go2-r.qn/b tions are given;

I. chemical → thermal → kinetic → electrical
II. kinetic → kinetic → electrical
III. gravitational potential → kinetic → electrical
Which row correctly matches the type of power station with the energy transformations?

  Which of the following pairs constitutes a r 0drf *of0p4zwenewable and non-renewable source of enfrd0f*o w4p 0zergy?

  Which of the following pairs constitutes a renewable and non-renewable source gl wala933 rl6of energyaalw39rll g36 ?

  Which of the following is a non-renewable energy resource,add/k 4zi ph)sle4y,?

  Which of the following energy 8riqf5q z2 ek4/6iddot* he,bresources is non-renewable?

  The government of a medium sized city plans to replace coan7wzp6nfn ;1h ou2n1jl power plants with photovoltaic cells 1 wz;jfn2 n7unhn16 poto power the city.
The following data are available:
Total area available for photovoltaic cells = 62.6$km^2$
Maximum intensity of light incident on photovoltaic cells = $1.36\times10^3$ $Wm^{−2}$
Average efficiency of energy conversion in photovoltaic cells = 20 %
Hours of sunshine in one month = 150 hours
1.Explain why the government's choice to reduce its reliance on coal would be beneficial to the Earth's climate.
2.Outline, in terms of energy changes, how electrical energy is generated from coal.
3.Using the data given, calculate in $GJ$ the maximum expected energy generation for one month. $Electrical energy obtained$ =    $\times10^6\,GJ$

  The average radius of Nehs+/-(l5orxjvy21 u zd brjy ,ptune's orbit around the Sun is approximately 30 times the orb(+hjboxd 2zvjys ,/ r-lu15ryital radius of earth. Estimate the solar constant of Neptune.

  The following three statements givwzb jmr6 y;( uyg/u9y6e possible reasons why the average intensity of sunlight incident on a solar panel during a 6b/r9y;y(jm u6 ywz guday on earth is only a fraction of the solar constant.
I. Scattering of sunlight in the atmosphere
II. Rotation of the earth
III. The surface of the solar panel is not perpendicular to incident of sunlight
Which of the statements are correct?

  Several energy conversions2uoc)t0 pjl(yj 2gimpf 4o2 c) occur in power stations. Examples of electricity generation that both involv c42oy)2tl()uom gipf2 0jpj ce energy transfer from thermal to electrical are

  The albedo at the poles ou/w+ oz d-,u5( f:bbpv9qjckef Earth during a particular day is 0.8. What is the value of the absorbed intcw:+b9 bfj,/u -kqe5( udopvzensity if the solar intensity is 700 $Wm^{−2}$?

  The sun radiates energy to the surface of the earth. Some of this ener6k2qk l, jxxlpq a5n)0gy is scattered and the rest reaches thexp k0l)ql 6xk,nqa j52 earth's surface.



1.Differentiate between heat transfer methods: conduction, convection and thermal radiation.
2.At any given time, the power of the radiation of the sun absorbed by the earth's surface is $P$.
$P$is given by
$P\,=\,(1−α)SπR^2$
Where $α$ is the albedo of the earth’s surface.
(1)Show that the average intensity of radiation $I_{avg}$​ that is absorbed by the earth's surface is given by $I_{avg}$​=$\frac{(1−α)S}{4}$. ​
(2)Calculate the average intensity of the radiation that is absorbed by the earth's surface. The earth's albedo is 0.3. $I_{avg}$ =    $Wm^{-2}$
Some of the infrared radiation from the earth is absorbed and reradiated by the greenhouse gasses.
3.Explain this absorption and emission of radiation in terms of molecular energy levels.

  On a certain day, the solar intensity onuxd4olyaag + 8pww2cu z056z ; the Earth's surface is 300 $Wm^{−2}$. Photovoltaic cells which have an efficiency of 20% are used to convert solar energy to electrical energy. What should be the minimum area of the photovoltaic cells to produce an output of 6.0 kW assuming that the incident light is normal to the surface of the panel?

  A natural gas plant burns fuel with a specific energy of omt(/tb;9imi 1 y e0wxz0yx:u80$MJkg^{−1}$.
The rate of energy input of the natural gas is 1.6$GW$. What is the rate at which the fuel burns?

  1.(1)Define the albedn:dxwj ;on-s7 9lw2bso of a body
(2)It was suggested that painting rocky mountain tops with a white chalk-based paint could help reduce the impact of global warming. In terms of albedo, explain why this could work.
2.(1)Given that the radius of the earth is $6.4\times10^6\,m$, show that at any given time, the total amount of energy incident on the earth's surface is approximately $1.8\times10^{17}\,J$ per second. P =    $\times10^{17}\,W$
(2)The average albedo of the Earth is 0.30. What is the rate at which the Earth absorbs energy from the sun?
(3)Using your answer from (b)(ii) and ignoring atmospheric effects, estimate the average temperature of the earth for which equilibrium would be established. Assume the earth's average emissivity is 0.80.T =    K
(4)Greenhouse gases in the atmosphere elevate the average temperature of the earth such that it is higher than the answer found in (b)(iii). Explain the mechanism by which this occurs.