 तो जाहातक गे एनजी एकनामिक्स का तालुख है आना के नीचाताता, किस में पूलितिक्स कोई उसका अंटर्टक्म्स हो, लेकिन वो उता आपके पूलितिक्स असी है के, के लिए दिन्तिग्रेते पारत फारत है मारे कल्चर का. तो एनेची इक्नामिख्स कभी वुए,트가 इक्नामिख्स कभी है। फोली कल इक्नामिख्س नहींउआ, भलके जीग्राफिक इक्नामिख्स, जीगिलघ्गल इक्नामिक्स, उसा अरे अग खाकतर सेंग, बोसार लिसके लिक्सारिस में इंक्लूडवोतेहे ही, रदश्ति में लास्तांग, फिछ ले एक एक मरडूल में सभंजाया दा, के जो भाब के अप्फ़न्ट खोस जो हुती है, और गो मैंटल्धिन्नान्च कोस जो हुती है, को जो तो चीजन जो है. तो वह में सभ में कच्च्ना गृजिसके अनटर है. अब लेंद वेलिए है, लेंद वेलिए के एक पलटिकल वो है ना कुछ ना कुछ अच्टिस्त की अनदर, तो वो सब उसके अनदर यकनन शुपे वे जुर होतें, लिकन होतें जुर है. तो लेकन उन सब से उपर चीज़ ना सब से बुन्यादी चीज़ है, वो साँन्टिक का कुछ अच्टिडरेशन इस के लिए, तो उसके लिए थोडो चा चीज़न समजनी पडेंगी के यह पोटो वोल्टेक्स के पीचे साँन्स क्या होती, तो पोटो वोल्टेक्स का मजज़ार बात यह नहीं के, जितने भी, हमने बाखी चीज़े देखीं जिस से भीजली बनती थी, उसके तीन चार स्टेप से हैं, यह ना, आप जैसे कोला जिला यह तो कोला से कमिकल एनरजी से, फिर विजली जा के बनी, चार पाज स्टेप में, और हर एक स्टेप में लोस होता है, सोलर सेल्स की एक अड़ाईज बहुत बड़ी है, कि सरफ एक स्टेप है, सुरा जाया और भिजली बनी, सुरा जाया और भिजली बनी, direct conversion of solar light into electricity, that is photovoltaics. तो उसकी के से होती है, तो उसके बारे में थोड़ा से light के बारे में भी देखना पड़ेगा, फिर जाया के में आपको सोलर सेल के लिए आगे वाले मोडिल में, पता हुँँँँँ, कि सोलर सेल चलता कै से, तो सोली सी, ज़रा सी basic physics समज लही शके लिए, तो आपको ये ये यो electromagnetic spectrum है, electromagnetic spectrum में जिस में आप पुरा क्यमारे से लेके, और radio waves तक के पुरा जाते है, जिसकी energy बहुत साथा अद और बहुत कम है, तो वो पुरे spectrum, valid है, तो सोलर energy के उपर, लेके न सारी चीजा नहीं अहीं करेंगे, ये चोडा सा इसका एक बीच का जो हिससचा है, जो visible light वाला हिसचा है, वो से इस्तमाल करेंगे, तो ये visible light का जो section है, 400 nanometer to 750 nanometer, ये है, वो हिससचा जो हमारे लिए नभारनट है, अब ये क्या नमबर का क्या मतला है, 400 nanometer to 750 nanometer, ये वेव लेंत हुई, के जो वेव आती है, ये आप जो light होती है, वो तो particle वेव भी है, तो ये वेव लेंत जो होती होती है, एक जान से, where it starts, where the wave starts, where the wave ends, that length is called the wave length. ये जो 400 nanometer of 750 nanometer, nanometer का मतला है, 10 to minus 9 meter. तो ये वो है उसकी वेव लेंत के अंदर, अप विस में वेव लेंत में, जो visible light हो आप आपने देख ली, infrared जो heat है, वो visible light से उसकी energy कम होती है, तो wave length जआदा होती है, इस का मतला है, energy of wave length यो होगा, inversely proportional ए एक जुसरे से, वेव लेंत बदती जाएगे, रेटीो वेव थे हैं जासे, रेटीो वेव खी एनरजी तो बहुत कम होती है, अप जो आप सुनते है, रेटीो पे कोन सुनता है, बड़ी कम आसे सुनाई देख लेके, परस की जेसे मेरे पास ये है, oo . , , , , , , , , , , , , , , , अभकी तो लोग लिएंत खने से की कुई उनलाल भी बलस्एँ थे, किजकी सकतर आबा, एक ज़ी करे लाडनी से नग्यों पहडोग. अब ये इसकी बडिसारी जीजी आप आप प्लिकेशन देखे है, जो स्ताब साँन है, जो ब्रेक लाएट हो, सब लाल होती है, लाल क्यों होती है, इस वेजा से होती है, कि वेव लेंत आब यहां देखे है, लाल जो है वो राएट साइट प्याती है, आब वो वो पार्टिकल जीजी हवाए में, जिसकी वेजा से लाइट स्केतर होती है, वो उन से थोडी सी आगे है, तो इसका मतब जितने भी पार्टिकल है, उसके अतराफ वो लाल लाएट हो के चली जाती है, तो बहुत दूर से नदर आजाती है, अगर पीचे जाएंगे अगर भूलु लाइट में देशाइन देखेंगे, वो नदर नहीं आए प्र आपको जाजा दूर से, तो इस वज़ा साडे जो है वो लाइट जो है, असमान वो नीला क्यों होता है, योंके वो जो भूलु लाइट जो है, वो पार्टिकल साइस यह वेपर साइस यह गैस मालिकुस जो है, अवारे आतमसपीर के अंदर, वो इस तना से स्केटर करतें, के से बूलु लाइट यह वो वामारी डरेक्षन में आती है, तो यह सार है, वेवलेंट के चक कर है, यह सार है, तो एनरजी और वेवलेंट का मैं आप को बताया, अब एक और चीज होती होती है, जिस है, फ्रीक्वेंसी, के एक सेक्टिन हमारे काूंट कर है, तो कितनी वेवस उसके अंदर गूजेंगी, हरज आप में सुने एक, वो हरज जी है, how many number of waves per second, तो वो एक ऊन्सेबत है, हरज जी है, वेवलेंट यह के फ्रीक्वेंसी जो है, नमबर अ वेवनट पर सेक्टिन, नमबर अ वेवस पर सेक्टिन कर, यह नरजी कर जी होगा, जाातन में नमबर अप वस होगा, number of waves, it will have a lot of frequency, it will have a lot of energy. And I have told you about energy first, that it is ultra related to wavelengths, if there is a lot of wavelengths, the energy will be reduced. This means the frequency and the inverse proportionality of the wavelength. If there is a lot of frequency, the wavelength will be reduced. If there is a lot of frequency, the wavelength will be reduced. And then I have already told you about the connection of the energy. These are two or three things, which are easy to understand. So, this is what we have, the light from the sun, as you know, the light of the sun, all these values are in it, all these are the spectrum, from the violet to the red, it is called Droid-G-Biv, red, orange, yellow, green, blue, indigo and violet. So, all these things are in it, all these are show. Okay, these are all lights, all these are electromagnetic waves, okay? Now, I have asked this question, at what speed do these waves travel to earth? These are the currents of 1,86,000 mph, all these are the same things, you can take them as X-rays, you can take any of them, all the speeds are the same, electromagnetic waves. So, these are the spectrum of the visible, violet and red, both are the ends, but there is no difference in their speed, the waves which are coming, the particles which are coming, they are from 1,86,000 mph, or 3 times 10 to the 8 meters per second. So, this is the speed, so this is the connection, this is the speed, and then the frequency, and wavelength and energy, frequency, wavelength and energy, these three connections are very important, to understand and keep in mind, so that the future, how to manipulate the light, how to bend it, all these things will come from it. So, this is the connection, if you understand, the one which I have written below, is equal to H-New Edge, which is a Planck's constant, E is directly proportional to Nu, Nu is the frequency, E is equal to H-C over lambda, C is the frequency of light, that is 1,86,000 mph, H is Planck's constant, lambda is wavelength, this comes with the energy, inversely proportional to lambda, the energy is directly proportional to Nu frequency and energy is inversely proportional to lambda, this relationship is only this, there is no complicated, it is a very easy relationship, keep them in your mind. Now, these things that I have told you, this is the graphical representation of it, all these things, look at the top graph from gamma rays, the most energy is from gamma rays, the most frequency is from gamma rays, now as you go to the left, their frequency will decrease, wavelength will increase, you can see it is very clear, now the gamma rays of 10-12 are in the nuclear size, after that you go to the X-ray, in the atomic size, then the ultraviolet is in the molecular size, then the visible bacteria, bacteria are near to 10-6, viruses near to 10-9 meters, so the bacteria are in the visible light, now infrared, we have seen the swedehaga, then the butterfly and the last radio wave, which is in meters, hundreds of meters, thousands of meters, then according to the big structures, they are formed, and all these things are not visible, all these waves are not visible, obviously X-rays you cannot see, ultraviolet you cannot see, gamma rays you cannot see, radio waves you cannot see, but what you see is the visible spectrum, that is 400-750 nanometer, all the solar cells that I will explain, infrared solar cells are also there, UV solar cells are also there, but they are very small, they are very small, then I will not talk much about them, I will talk more about the visible light solar cells, then we will talk about the spectrum that you can see, now this energy coming from the sun is its spectrum, on the left side, watt per meter square, how much it has irradiance, how much it has energy, watt is its power, power per meter square, what is the power density of it, which is coming down, and in the X-axis below, there are wave lengths, now look, yellow is in the whole continuous spectrum, but red is discontinuous, so yellow is completely theoretical, that will happen, in fact if we go out of our world, if we measure it from our atmosphere, then it will be yellow, where the sun starts coming into the atmosphere, then its absorption happens, what is the reason for absorption, all those things are written, because of water vapors, then because of UV vapors, because of carbon dioxide absorption, all that absorbs, O3 is ozone absorption, all these things that you are seeing, this is why it is discontinuous, that all these things absorb it, in this, the O3 written on the left-hand side, on the corner, on 250, this comes here, and the energy becomes so much, the wave length becomes so much, that that section is the section of UV, there is a little UV, 7-8%, the rest is visible, and here it is hot, the sun comes from the sun, the light comes or the heat comes, the heat is infrared, and the light is visible, there are two things in it, and what you have seen, this red one, this is what it shows, so that you can only understand it, that how much light has reached us, now I have explained the exact reason for this, in this the purple is ultraviolet, UV which is a little dangerous, which we will talk about later, the green one, all our work will only go through this, the rest is to leave the heat, it is just to eat, to eat the heat, to make the light, it is visible in the spectrum, we will have to use it, the purpose of this is to show, that how much energy is different from the wave length, now there are many suns in the space, like our sun, the sun, see its temperature, see the connection of the energy from the temperature, see the temperature of the spike, and see its energy, so the sun of the spike, out of which only UV comes out, it is very dangerous, very strong, after that the stars are like this, whose energy is so low that it only comes out of the infrared, so infrared means wave length, or you can see the connection of the energy from the temperature, now see if there is a bulb, there is a white light, there is an incadescent light, or I am only talking about incadescent, I am not talking about LED, that if it is white then it will be very hot, if it is red then it will be a little less hot, if it is not completely dark then there is no color, so the emission of the light of the temperature is very different, which light is emitting from it, so its direct effect is on the sun, about which we will talk more,