Ncert – class 8- science – Chapter 12: Some Natural Phenomena 1 Welcome to your Ncert - class 8- science - Chapter 12: Some Natural Phenomena 1 1. Why is Earthing done in buildings? To transfer extra current to air None of these To give extra strength to the building To protect us from electric shocks None 2. The process of transferring a charge from a charged body to the earth is called Discharging Electrolysis Earthing Hydrolysis None 3. What is a positive charge? The charge acquired by plastic straw when it is rubbed with a silk The charge acquired by a glass rod when it is rubbed with silk None of these The charge acquired by silk when it is rubbed with a glass rod None 4. Following are precautions one must take in case a storm is accompanied by lightning. i) Do not take shelter under a tree. ii) Do not take shelter under an umbrella with a metallic end. iii) Do not take shelter in open garages, storage sheds, etc. iv) Do not take shelter in a bus in the open. Which one of these is not correct? (i) (iii) (iv) (ii) None 5. Lightning is caused in the atmosphere primarily due to Discharge between one charged and one neutral cloud. Discharge between two similarly charged clouds. Opposite charges accumulation at edges of a cloud. None of these None 6. Which of the following is not a natural phenomenon? Earthquake Cooking Cyclone Lightening None 7. Some object can be charged by _________ with other objects. Heating Rubbing Joining Touching None 8. What happens when two bodies are rubbed together They get equal charged but the opposite nature None Nothing happend with rubbing They get equal charged but the same nature None 9. How does charges separate during a thunderstorm? Due to rubbing of air particles None of these Due to movement of air Due to movement of air current and water droplets None 10. If the Richter scale reading for an earthquake is less than 3.5 then what can you say about the earthquake? Often felt & rarely causes damage Causes major damage to poorly constructed buildigs Generally not felt but recorded Major earth quake causes serious damage None 11. In an electroscope, if aluminium strips are replaced by plastic strips, and a charged object is touched with the metal top of the electroscope: the plastic strips will not diverge the plastic strips will diverge the plastic strips will come more closer. one strip will move away while other will remain same. None 12. What is the cause for the streaks of bright light and sound produced during lightning? Meeting of like electric charges Meeting of positive charges Meeting of unlike electric charges Meeting of negative charges None 13. What are the weak zones around the boundaries of plates underneath Earth, which are prone to slide and cause earthquakes? Eruption zone Explosive zone Fault zone Sliding zone None 14. Two objects when rubbed together, get charged. The charges on them are: Equal and opposite Unequal and opposite Equal and similar Unequal and similar None 15. When a glass rod is rubbed with dry silk cloth, the charge acquired by the silk cloth is Negative Both positive and negative none of the above Positive None 16. An ebonite rod is rubbed with fur. The charge on the ebonite rod is ______ and the charge on the fur is _______. Negative, Negative Positive, Negative Positive, Positive Negative, Positive None 17. Which of the following natural phenomenon is most destructive in terms of loss of life and property? winds Lightening Storms Earthquake None 18. Like charges repel and unlike charge Any thing may happen Repel or attract Attract each other Repel each other None 19. Building can be protected from lightening by using Lightening rod at the top of building All of these Lightening rod on the levels of building Wooden logs at the top of building None 20. During the thunderstorm, ________ move upwards while ________ move downards. Water droplets, air currents Air currents, charges Air currents, water droplets Water droplets, charges None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to comment Enter your email address to comment Enter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
