BC-Science Welcome to your BC-Science Oxidation is a process which involves (a) addition of oxygen (b) addition of hydrogen (c) removal of oxygen (d) removal of hydrogen The process of reduction involves (a) addition of oxygen (b) addition of hydrogen (c) removal of oxygen (d) removal of hydrogen Give the ratio in which hydrogen and oxygen are present in water by volume. (a) 1:2 (b) 1:1 (c) 2:1 (d) 1:8 What type of chemical reactions take place when electricity is passed through water? (a) Displacement (b) Combination (c) Decomposition (d) Double displacement A substance added to food containing fats and oils is called: (a) Oxidant (b) Rancid (c) Coolant (d) Antioxidant Which one of the following salts does not contain water of crystallisation? (a) Blue vitriol (b) Baking soda (c) Washing soda (d) Gypsum Tomato is a natural source of which acid? (a) Acetic acid (b) Citric acid (c) Tartaric acid (d) Oxalic acid Na2CO3 . 10H2O is (a) washing soda (b) baking soda (c) bleaching powder (d) tartaric acid How many water molecules does hydrated calcium sulphate contain? (a) 5 (b) 10 (c) 7 (d) 2 Sodium carbonate is a basic salt because it is a salt of a (a) strong acid and strong base (b) weak acid and weak base (c) strong acid and weak base (d) weak acid and strong base Alkalis are (a) acids, which are soluble in water (b) acids, which are insoluble in water (c) bases, which are insoluble in water (d) bases, which are soluble in water Lime water reacts with chlorine to give (a) bleaching powder (b) baking powder (c) baking soda (d) washing soda The most abundant metal in the earth’s crust is (a) Iron (b) Aluminium (c) Calcium (d) Sodium The poorest conductor of heat among metals is (a) Lead (b) Mercury (c) Calcium (d) Sodium The highly reactive metals like Sodium, Potassium, Magnesium, etc. are extracted by the (a) electrolysis of their molten chloride (b) electrolysis of their molten oxides (c) reduction by aluminium (d) reduction by carbon Which of the following can make a parallel beam of light when light from a point source is incident on it? a) Concave mirror as well as convex lens (b) Convex mirror as well as concave lens (c) Two plane mirrors placed at 90° to each other (d) Concave mirror as well as concave lens A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is (a) -30 cm (b) -20 cm (c) -40cm (d) -60 cm Under which of the following conditions a concave mirror can form an image larger than the actual object? (a) When the object is kept at a distance equal to its radius of curvature (b) When object is kept at a distance less than its focal length (c) When object is placed between the focus and centre of curvature (d) When object is kept at a distance greater than its radius of curvature Magnification produced by a rear view mirror fitted in vehicles (a) is less than one (b) is more than one (c) is equal to one (d) can be more than or less than one depending upon the position of the object in front of it. A full length image of a distant tall building can definitely be seen by using (a) a concave mirror (b) a convex mirror (c) a plane mirror (d) both concave as well as plane mirror In torches, search lights and headlights of vehicles the bulb is placed (a) between the pole and the focus of the reflector (b) very near to the focus of the reflector (c) between the focus and centre of curvature of the reflector (d) at the centre of curvature of the reflector The laws of reflection hold good for (a) plane mirror only (b) concave mirror only (c) convex mirror only (d) all mirrors irrespective of their shape You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most? (a) Kerosene (b) Water (c) Mustard oil (d) Glycerine In which of the following, the image of an object placed at infinity will be highly diminished and point sized? (a) Concave mirror only (b) Convex mirror only (c) Convex lens only (d) Concave mirror, convex mirror, concave lens and convex lens Light travel fastest in (a) Water (b) Air (c) Glass (d) Diamond The mirror having reflection surface curved outward (a) plane mirror (b) concave mirror (c) convex mirror (d) cylindrical mirror The mirror having reflecting surface curved inwards (a) plane mirror (b) convex mirror (c) cylindrical mirror (d) concave mirror The mirror used as rear-view mirror in vehicles (a) convex mirror (b) plane mirror (c) cylindrical mirror (d) concave mirror The deviation of light ray from its path when it travels from one transparent medium to another transparent medium is called (a) reflection (b) refraction (c) dispersion (d) scattering Convex lens is also known as (a) converging lens (b) diverging lens (c) radial lens (d) axial lens The image which is formed behind the mirror+D4 (a) real image (b) virtual image (c) blue image (d) partial image Time's up
