Sujeet Kumar

Question 1.Match the pairs. Group A Group B a. C2H6 1. Unsaturated hydrocarbon b. C2H2 2. Molecular formula of an alcohol c. CH4O 3. Saturated hydrocarbon d. C3H6 4. Triple bond Question 2.Draw an electron dot structure of the following molecules. (Without showing the circles)a. Methane.Answer:Molecular formula: CH4 b. Ethene.Answer:Molecular formula: H2C = CH2 c. … Read more

Question 1.a. Alloy of sodium with mercury.Answer:Silver amalgam. b. Molecular formula of common ore of aluminium.Answer:Al2O3.nH2O c. The oxide that forms salt and water by reacting with both acid and base.Answer:Aluminium oxide (Al2O3). d. device used for grinding an ore.Answer:The device used for grinding an ore is grinding mill. e. The nonmetal having electrical conductivity.Answer:Graphite … Read more

Question 1.Match the columns in the following table and explain them: Column 1 Column 2 Column 3 Farsightedness Nearby object can be seen clearly Bifocal  lens Presbyopia Faraway object can be seen clearly Concave  lens Nearsightedness Problem of old age Convex  lens Answer: Column 1 Column 2 Column 3 Farsightedness Faraway object can be seen … Read more

Question 1.Fill in the blanks and explain the completed statements:a. Refractive index depends on the………….of light.Answer:Refractive index depends on the velocity of light.It is an experimental fact. (There is no question of explanation.) b. The change in…………of light rays while going from one medium to another is called refraction.Answer:The change in the direction of propagation of light rays while … Read more

Question 1.Fill in the blanks and rewrite the sentences:a. The amount of water vapour in air is determined in terms of its………..Answer:The amount of water vapour in air is determined in terms of its absolute humidity. b. If objects of equal masses are given equal heat, their final temperature will be different. This is due to … Read more

Question 1.Tell the odd one out. Give proper explanation.a. Fuse wire, bud conductor, rubber gloves, generator.Answer:Generator. It converts mechanical energy into electric energy, the remaining three do not. b. Voltmeter, Ammeter, gulvanometer, thermometer.Answer:Thermometer. It measures temperature, the remaining three measure electrical quantities. c. Loud speaker, microphone, electric motor, magnet.Answer:Magnet. It exerts a force on a … Read more

Question 1.Choose the correct option from the bracket and explain the statement giving reasons :(Oxidation, displacement, electrolysis, reduction, zinc, copper, double diplacement, decomposition) a. To prevent rusting, a laver of ……… metal is applied on iron sheets.Answer:To prevent rusting, a layer of zinc metal is applied on iron sheets.The rusting of iron is an oxidation process. … Read more

Periodic Classification Of Elements Question 1.Rearrange the columns 2 and 3 so as to match with the column 1. Column 1 Column 2 Column 3 i. Triad a. Lightest and negatively charged particle in all the atoms 1. Mendeleev ii. Octave b. Concentrated mass and positive charge 2. Thomson iii. Atomic number c. Average of … Read more

Exercise Question 1.Study the entries in the following table and rewrite them putting the connected items in a single row : I II III Mass m/s2 Zero at the centre of the earth Weight kg Measure of inertia Acceleration due to gravity N.m2/kg2 Same in the entire universe Gravitational constant N Depends on height Answer: … Read more

Question 1. In the adjoining figure, A is the centre of the circle. ∠ABC = 45° and AC = 7√2 cm. Find the area of segment BXC, (π = 3.14)Solution:In ∆ABC,AC = AB … [Radii of same circle]∴ ∠ABC = ∠ACB …[Isosceles triangle theorem]∴ ∠ABC = ∠ACB = 45°In ∆ABC,∠ABC + ∠ACB + ∠BAC = 180° … Read more