Physics – Important Points
* Colour Blindness was first discovered by Horner (1976)
* 3D image is known as Hologram
* Human eyes have convex lens
* Raman effect is related to Scattering
* Heat energy are transmitted as Infra Red Rays
* Speed of Light is maximum in Vaccum
* Focal Distance of lens is maximum for Red Light and minimum for Violet light
* Magnifying Glass is Convex Lens of small focal length
* Power measures the degree of divergence or convergence and is measured in Diopetres
* If a transparent material is invisible in any liquid , then both of them have same refractive index
* Rainbow are always formed in direction opposite to the sun
* Bolometer is used for detection of Infra Red rays
* The direction of wave is independent of velocity , wavelength and frequency
* Positive sign is for convergence or a convex lens
* Negative sign denotes divergence or a concave lens
* Power of Sunglass is Zero
* Hypo or Radium Thiosulphate is used for fusing in Photography
* Refractive index of a material is independent of angle of incidence
* The frequency of visible light varies betwen 400nm to 700nm
* Logitudnal Waves can’t be polarized
* There is no change in frequency of sound when it changes medium but its velocity, direction and intensity will be changed
* Ammonia is used as a coolant in refrigerator
* Specific Heat of water is 1 calorie/gram °C
* Audible Frequency ranges from 20 Hz to 20,000 Hz
* If there is a relative motion between the source and the observer, then the frequency of sound heard by the observer might be different from the frequency of the source (Doppler’s effect)
* As temperature of medium increases, its refractive index increases
* The first use of telescope for research was by Galelio of Italy in 1609
* At room temperature velocity of sound is 330m/sec