Question 1 What is night blindness? What causes night blindness? Question 2 How does eye adjust itself to deal with light of varying intensity? Question 3 Why we cannot see our surrounding clearly when we enter a darkened cinema hall from bright sunshine but our vision improves after some time? Question 4 How does the eye lens differ form the ordinary convex lens made … [Read more...] about Human Eye
Class 8
Formation of Image, Periscope, Kaleidoscope
Question 1 State few characteristics of image formed by a plane mirror? Question 2 What is a periscope? Question 3 State the various uses of periscope? Question 4 Explain how a hair dresser makes you see hair at the back of your head after the hair cut is complete? Question 5 How many images of an object will be formed when the object is placed two plane mirrors … [Read more...] about Formation of Image, Periscope, Kaleidoscope
Reflection of Light
Question 1 What is meant by luminous object? Give example? Question 2 What is meant by non-luminous objects?Give example? Question 3 Define the term reflection of light? Question 4 What is meant by incident ray? Question 5 What is meant by reflected ray? Question 6 What do you mean by point of incidence? Question 7 Define the angle of incidence? Question 8 … [Read more...] about Reflection of Light
Earthquake
Question 1 What is an earthquake? Question 2 Define the term epicentre and focus of an earthquake? Question 3 What are the main situations in which earthquake occurs? Question 4 What are the various effects of an earthquake? Question 5 Name the three layers of earth? Question 6 What is a seismograph? Question 7 What precautions should be taken by people living in seismic … [Read more...] about Earthquake
Lightning
Question 1 How is lightning produced between clouds in the sky? Question 2 Why does lightning usually strike tall building? Question 3 How does a lightning conductor protects a tall building? Question 4 Why are lightning strikes more frequent in hilly areas? Question 5 Name the materials of which a lightning conductor is made? Question 6 What is a lightning … [Read more...] about Lightning
Electric charges
Question 1 What are the two kinds of electric charges? Question 2 Why does a plastic comb rubbed with dry hair attract tiny pieces of paper? Question 3 What is lightning? Question 4 Explain why a charged balloon is repelled by another charged balloon? Question 5 Explain why a god rod can be charged by rubbing when held in hand but an iron rod cannot be charged by … [Read more...] about Electric charges
Uses of electroplating
Question 1 Name two metals which are usually electroplated on cheaper metals for making jewellery? Question 2 What properties of chromium make it suitable for electroplating it on car bumpers, bath taps and bicycle handlebar? Question 3 What properties of tin make it suitable for storing food? Question 4 Which is the polluting waste generated by electroplating … [Read more...] about Uses of electroplating
Purification of metal
Question 1 Name few application of chemical effects of electric current? Question 2 Name few compounds which are produced by using chemical effect of current? Question 3 Name 2 metals which are purified by using the chemical effect of current? Question 4 Describe how you will purify a strip of impure copper by using chemical effect of electric current? Purification … [Read more...] about Purification of metal
Weak conductors of electricity
Question 1 How will you show that vinegar and lemon juice are weak conductors of electricity? Question 2 How will you show that ordinary water or tap water is a weak conductor of electricity? When an electric current is passed through vinegar taken in a beaker ,then the bulb glows very dimly. The very dim glowing of bulb indicates that though vinegar and lemon … [Read more...] about Weak conductors of electricity