Ncert – class 8- science – Chapter 12: Some Natural Phenomena 2 Welcome to your Ncert - class 8- science - Chapter 12: Some Natural Phenomena 2 1. Clouds get electrically charged when : Air molecules rub against water molecules Both Air molecules rub against water molecules and Cold currents of air rub against hot currents of air The UV rays of sun falls on them Cold currents of air rub against hot currents of air None 2. __________ is engineered to protect an elevated structure in the event of lightning strike. A lightening shield Copper wire A lightning conductor All of the above None 3. A lightning conductor consists of several sharp metal spiked connected to a thick copper strip. a metal plate buried deep inside the ground connected to the ground end of copper strip. a conductor fixed on top of the building. all of the above None 4. Other than lightning conductor, what are the objects which indirectly protect building from lightning / thunderstorm? Electrical wires in the building. Metal column used during construction. Water pipe in the building. All of the above. None 5. The lightning conductor used in building, protects the building by: Absorbing the electric charge Conducting the lightning safely to the ground None of these Dissipating the electric charge away from the building None 6. The sparks caused due to friction between two machine parts are: none of the above lightning on a very small scale not similar to lightning similar to lighting None 7. Why shouldn't one stand under a tree or a tall building during a thunderstorm? Trees and buildings may fall causing damage, Trees and buildings do not offer enough escape ground, None of the above, Lightning can strike trees and buildings, None 8. Suppose you are in a car and it is raining heavily with thunderstorms. Then what is the best way to protect yourself from a possible lightning strike? Run to a nearby tree Remain in the car Get out and stand under an electric pole Get out of the car and take cover under the car None 9. Why are lightning conductors pointed in shape? To reduce mass. It attracts more electric charge due to very small radius and hence small surface area. It allows more current. It repels the incident lightning discharge. None 10. Explore and answer :Some children are playing in the playground. Suddenly clouds gather in the sky and there is thunder and lightning. What should they do now?The children should_______.Choose the correct answer. Stand under a tree Squat down Just stand at their places Run to their houses None 11. Lightning is a more common phenomenon during rainy season because of: high humidity high atmospheric density solar electrostatic disturbances moderate temperature None 12. Rub a glass tumbler with wool. Bring an inflated charged balloon, rubbed with wool, near refill. Then the balloon will burst. both balloon and tumbler will repel each other. no reaction will be observed. both balloon and tumbler attract each other. None 13. What happens when you touch the water pipeline in the building during a thunderstorm? All of the above Your body provides earthing Charges will pass through your body Your body will conduct electricity None 14. Which of the following one must do when caught in a Thunderstorm? Sit near a window Take shelter inside an isolated tree Take shelter under an umbrella with a metallic end Take shelter in a safe place like car or bus None 15. What kind of material should be used in an earthquake prone area? heavy weight light weight any of the above conducting material 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.
