A few sample questions from the CBSE Class 10 Science sample paper 2019 are given below:
Question 1. Name a common nutrient that is absorbed in the small intestine and reabsorbed by the kidney tubules.
Question 2. The presence of a particular group of bacteria in water bodies indicates contamination. Identify the group.
Question 3. How is Magnesium Chloride formed by the transfer of electrons? Why does the solution of Magnesium chloride conduct electricity?
Question 4. For the same angle of incidence in media A,B and C, the angles of refraction are 20o, 30o and 40o respectively. In which medium will the velocity of light be maximum? Give reason in support of your answer.
Question 5. The electronic configuration of an element ‘X’ is 2, 8, 6. To which group and period of the modern periodic table does ‘X’ belong? State it valency and justify your answer in each case.
Question 6. The figure below shows three cylindrical copper conductors along with their face areas and lengths. Compare the resistance and the resistivity of the three conductors. Justify your answer.
Question 7. The flow of energy between various components of the environment has been extensively studied. Give an outline of the findings.
(a) How will you show experimentally that metals are good conductors of heat.
(b) Describe the extraction of Mercury metal from its ore Cinnabar (HgS).
Question 9. A compound A (C2H4O2) reacts with Na metal to form a compound ‘B’ and evolves a gas which burns with a pop sound. Compound ‘A’ on treatment with an alcohol ‘C’ in presence of an acid forms a Sweet smelling compound ‘D’(C4H8O2). On addition of NaOH to ‘D’ gives back B and C. Identify A, B, C and D write the reactions involved.
(a) What is meant by the term ‘power of accommodation’? Name the component of eye that is responsible for the power of accommodation.
(b) A student sitting at the back bench in a class has difficulty in reading. What could be his defect of vision? Draw ray diagrams to illustrate the image formation of the blackboard when he is seated at the (i) back seat (ii) front seat. State two possible causes of this defect. Explain the method of correcting this defect with the help of a ray diagram.