CBSE ADDA

Discovery of Cell Robert Hooke at first examining a thin slice of dead cork [the bark of a tree] through a self-designed microscope in 1665. Robert Hooke predicts that the cork resembled the structure of a honeycomb consisting of many little boxes. He called these boxes cells. He described about this in his book “Micrographic”.  Cell is a Latin word which means ‘a little room’. The word cell was derived from a Greek word “Cellulae” which means small room. First living cell was discovered by A.V. Leeuwenhoek with the improved microscope in pond water. Q. What are Living Organisms made up of? Answer: All living organisms that we observe around us are made up of cells. Q. Who gave the cell theory? What does it state? Which organism is an exception of cell theory? Answer: Two biologists, “Schleiden and Schwann” gave the “Cell theory” which was later on expanded by “Rudolf Virchow”. Cell theory states that (a) All plants and animals are composed of cells. (b) Cell is the ba

1. Radiation (a) does not require any medium (b) is the process of transfer of heat in liquids (c) is the process of transfer of heat in which heat traveles in one direction. (d) Occurs in solids. 2. A Thermos flask prevents loss or gain of heat by a. conductions only b. convections only c. radiation only d. all the above 3. Handles of cooking utensils should be made of material that a. conducts heat well b. does not conduct heat c. radiate heat well d. does not radiate heat 4. Sea breeze and land breeze a. are caused by currents set up in air due to conduction b. are caused by currents set up in air due to convection c. are caused by currents set up in air due to radiation d. have no relation to conduction, convection and radiation 5. Which of the following is the best heat insulator a. air b. steel c. copper d. iron 6. He

Formative and Summative assessments 8 th Science Power Topic For Group discussion: Q. Saving paper helps to conserve our natural resources. Organize a seminar on the topic : Flora and fauna and its diversity. Prepare a project report on the wild life which has reached on the verged of extinct. General Questions: 1. Define these terms: a. Flora: The plants found in a particular area is called flora of that area b. Wild life sanctuary Wildlife sanctuaries is protected area reserved for wild animals, birds and plants c. Biosphere reserve The protected area in which multiple use of land is permitted to conserve biodiversity. d. Fauna The animals found in a particular area are called fauna of that area. 2. Differentiate between the following: a. Endangered and Extinct species b. Endemic and exotic species 3. Answer these Questions: a. What is red Data book? Answer: Red data book contain a record of all those species of plants and animal which are unde

CBSE PHYSICS: IX Motion And Rest Formative Check Points For FA-01.. : Q. Define terms (i) One radian (ii)  Angular displacement (iii) Angular velocity Answer: One radian is defined as the angle subtended at the centre of the circle by an arc equal in length to its radius. Angular displacement : In a circular motion, the angular displacement of a body is the angle subtended by the body at the centre in a given interval of time. It is represented by the symbol  q  (theta).                                Angular velocity : The angular displacement per unit time is called the angular velocity. it is represented by the symbol  w (omega). Angular velocity  w  =  q /t In figure, the arc AB of the circle has length  l   and subtends an angle  q  at the centre C Click on given link to read full post:   Check Points For FA-01