pa science teachers

A force of 980 N acts on a body for 0.1 seconds. Calculate the change in momentum of the bod..

A variety of produce could be obtained from a single crop to meet the varying requirements of the family like cereals, pulses, vegetables et..

A species is considered extinct when there is no reasonable doubt that its last individual has died, e.g., mountain quail, pink headed duck, one horned rhino and cheeta..

A neutral salt arises due to the neutralization reaction. Here, salts of strong acid and strong base combine to form such salts that show a neutral pH of ..

A man's characteristics, such as height, colour of the eyes, intelligence, etc. are all inheritable. Often we see that the children of parents with blue eyes would get blue eyes; baldness passes on in the family from one generation to another; even disorders like diabetes and heart diseases a..

A pair of seminal vesicles are glands that are present behind the urinary bladder. Each sperm duct has the seminal vesicle of its side secreting a fluid into the common ejaculatory duct. This fluid along with the sperms is called the semen , a milky flui..

A naturally occurring sample of Lithium contains 7.42% of 6 Li and 92.58% of 7 Li. The relative mass of 6 Li is 6.015 and that of 7 Li is 7.016. Calculate the atomic mass of a naturally occurring sample of lithiu..

Every organism, whether its body is unicellular or multicellular, is capable of performing all vital functions such as respiration, ingestion, excretion and reproduction. In multicellular organisms, because of the increase in body size, it is difficult for each cell to efficiently cope with the vas..

A normal eye can see all objects over a wide range of distances i.e., from 25 cm to infinity. But due to certain abnormalities the eye is not able see objects over such a wide range of distances and such an eye is said to be defective. Some of the defects of vision are Hypermetropia or long..

A lens is a portion of a transparent refracting medium bounded by two surfaces which are generally spherical or cylindrical or one curved and one plane surface. Basically, the lenses are classified as convex lens or converging lens concave or diverging len..