Roman Saini is teaching live on Unacademy Plus
151. Which of the following is an electrical conductor? a. Human body. b. Glass. c. Wood d. Rock
Answer: a Explanation: Materials that allow electric current to pass through them are called conductors.
0152. Which of the following objects is not magnetic in character? a. Iron. b. Nickel. C. Cobalt. d. Magnesium
Answer:d Explanation: The materials which get attracted towards a magnet are magnetic for example, iron, nickel or cobalt.
Q153. A freely suspended bar magnet always stops in a. East-west direction b. North-south direction c. Vertical direction d. Never stops at all.
Answer: b Explanation: A freely suspended bar magnet always stops in the North-south direction because it gets aligned with earth's magnetism, which has a north-south direction. This property of the magnet is very useful for us. For centuries, travellers have been making use of this property of magnets to find directions. Later on, compass was developed based on this property of magnets A freey suspended bar maa garth's
Q154. Water does not enter into an empty bottle placed vertically in a tub of water; a. Due to gravity. b. Due to air present inside the bottle. c. Due to surface tension of water. d. Due to shape of the bottle.
Answer: b Explanation: Water does not enter the bottle when it is in an inverted position, as there is no space for air to escape. When the bottle is tilted, the air is able to come out in the form of bubbles, and water fills up the empty space that the air had occupied.
Q155. Where do bubbles formed in boiling water come from? a. Gasses dissolved in the water. b. Photosynthesis of microorganisms present in water. c. Atmosphere d. Decaying matter ses disoved in the woter- ms presentin
Answer: a Explanation: Increased temperature causes an increase in kinetic energy. The higher kinetic energy causes more motion in the gas molecules which break intermolecular bonds and escape from solution.
0156. Where do bubbles formed when water is poured on soil come from? a. Air present in the soil. b. Photosynthesis of microorganisms present in the soil. c. Atmosphere d. Decaying matter.
Answer: a Explanation: When the water is poured on the lump of soil, it displaces the air present in the soil which is seen in the form of bubbles.
Answer: b Explanation: Converting plant and animal waste including that from kitchen, into manure, is called composting.
Q159. Kharif crops are grown during,; a. Rainy season b. Winter season c. Autumn season d. All seasons
Answer: a Explanation: Self-explanatory
0161. Which of the following is not a rabi crop? a. Gram b. Pea c. Mustard d. Cotton
Answer:d Explanation: Self-explanatory
Q163. Why are seeds floating in water not used for sowing? a. Because they contain a lot of air inside them. b. Because they contain insects which breathe out carbon dioxide and make the seeds lighter. Because the seeds are damaged and hollow, due to which they float in water. Because floating seeds do not give much yield c. d.
Q164. Consider the following statements: 1. Manure is produced naturally. 2. Fertilizers are chemical substances prepared synthetically Choose the correct statement / statements. a. 1 only b. 2 only c. Both 1 and 2 d. None of the above
Q165. NPK in a chemical fertilizer refers to; a. Nitrogen, phosphorus and calcium. b. Nitrogen, phosphorus and potassium. c. New product from Korea. d. Non phosphorus potassium.
Answer: b Explanation: Self-explanatory