3024.75 Joules needed to warm iron
The incoming and outgoing energy at the Earth’s surface must balance. Or in other words, the flow of energy into the atmosphere must be balanced by an equal flow of energy out of the atmosphere and back to space.<span>
Earth's Energy balance describes how the incoming energy from the sun is used and returned to space. All </span>of the energy entering earth’s atmosphere comes from the sun. Half of it is absorbed by the earth’s surface i.e. the land and oceans, 30% is directly reflected back to space by clouds and 20% is absorbed by the atmosphere and clouds.<span>Earth's </span>actual<span> average global temperature is around 14° C (57 F).</span>
Isotope- variation of an element
Sixteen- atomic number of oxygen
Q=mc\Delta T
Q= 40.5g x 0.900 J/g degree Celsius x 7.5
Q= 273.4 J.
Even if it is cooled , we use the same temperature as heating it.
Real and virtual images.<span> In a dark room one can form an image of a candle flame on a white screen by letting the rays from the candle pass through a small opening. See Fig. 1. This idea is used in the pinhole camera. The pinhole camera is simply a light-proof box with a tiny pinhole in the front and photographic film stretched across the rear wall. See Fig. 2. One uncovers the pinhole for a minute or so, then covers it back up, to take a picture. If it is held steady, it can take a good picture. If one replaces the pinhole with a lens, the intensity of the incident light is increased and a sharp image can be recorded in a fraction of a second. The image formed by a pinhole or a lens is formed by incident rays of light on a surface and stands in contrast to another kind of image — the kind of image formed by a mirror. The image formed by a mirror is not real, it is an illusion formed by the way the light reflects off the mirror. The image seen in a mirror looks three dimensional and real but we know there is nothing where the image appears to be. An image such as that formed by a pinhole or lens is called a </span>real image<span>. An image such as that formed by a mirror is called a </span>virtual<span> image</span>
