05-01-2018, 04:34 PM
*Focal length and power of a convex lens is always positive.
*When a convex lens is placed in water its focal length
Ans : Increases
*Power of a lens increases as its focal length decreases.
*Power is the reciprocal of focal length P = 1/f
*Persistence of vision of human eye is 1/16 seconds.
*Speed of Modem movies is 24 frames per seconds.
Do you know
*Short sight can be rectified by using
Ans : Concave lens
*Long sight can be rectified by using
Ans : Convex lens
Mirrors
*A concave mirror form a virtual or real image depending on the position of object.
*Concave mirror is also used by dentists and ENT doctors.
*The image obtained from a light ray that do not actually come from the point of source is called virtual image
*A real image is formed by the actual intersection of rays.
*The reflector behind a spot lamp or car head lamp is parabolic.
*In plane mirror the size of the object and image are same.
*The shortest height of a plane mirror required to view the full size image of a person of height ‘L’ cm is L/2 cm.
Nobel prizesi in Physics
*1901- Whilhelm Rontgen
*1903 - Henri Becquerel, Pierre Curie, Marry Curie
*1904 - Lord Rayleigh
*1906 - JJ.Thomson
*1909 - Marconi, Karl Braun
*1913 - Kamerlingh Onnes
*1915 - William Henry Bragg and William Lawrence Bragg
*1918 - Max Planck
*1922 - Niels Bohr
*1930 - C.V. Raman
*1967 - Hans Bethe
*1969 - Murray Gell-Man
*1983 - Subrahmanyan Chandrasekhar, William Fowler
*2001 - Eric Cornell, Carl Wieman,Wolfgang Ketterle
*2013 - Francois Englert, Peter Higgs
*2014 - Isamu Akasaki, Hiroshi Amano, Shuji Nakamura
*2015 - Arthur B. Me Donald, Takkaki Kajita
*2016 - J. Mochael Kosterlitz,Duncan Haldane,David J. Thouless
