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