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  SCIENCEIMPORTANT POINTS FOR X BOARD EXAMINATION

 Concave mirror mostly forms real images, which can bereceived on the screen; convex mirror forms virtual

images, which cannot be received on the screen. 

Concave mirrors are used as shaving and make upmirrors.

 Radius of curvature (R) = 2 X focal length (f)

 The ratio of the height of the image to the height of theobject is known as the magnification.

 The distance of the closest point from the eye that canbe seen clearly without accommodation is known asleast distance of distinct vision.

 In myopia distant objects are not clearly visible. It iscorrected by using concave lens.

 In hypermetropia, nearby objects are not clearly visible.It is corrected by using convex lens.

 Sun appears to rise 2 minutes earlier and set 2 minuteslater due to atmospheric refraction.

 

Fission, fragmentation, regeneration, budding,vegetative propagation and spore formation are variousmodes of asexual reproduction.

 Stamen, the male reproductive part of flower, is madeup of anther and filament. Carpel is the femalereproductive part and is composed of stigma, style andovary.

 Following fertilization, the ovule develops into seedwhereas the ovary forms the fruit. On germination, theseed develops into a seedling.

 Pollination is the transfer of pollen grains from antherto stigma. It may be either self- or cross-pollination.

Dr. P. N. PATHAK SASARAM, BIHAR