Q19. When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

 

Q20. Which metal is usually electroplated on car parts such as bumpers and bicycle handlebars made of steel?

 

Q21. Which metal is electroplated on iron for making cans and why?

 

Q22. Why is the current in the circuit weak?

 

Q23. Why do brand new cycles have shiny handlebars and wheel rims what will happen if these are scratched?

 

Q24. Why is it dangerous to touch a working electrical appliance with wet hands?

 

Q25. Write two common application of the chemical effect of electric current.

 

Q26. For electroplating copper on an iron object, which terminal of the battery (positive or negative) is connected to the iron object?

 

Q27. In case of a fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.

 

Q28. Why the bulb glows when the electric current passes through it?

 

Q29. What is meant by the chemical effect of electric current? Give an example.

 

Q30. Which properties of chromium metal make it suitable for electroplating?

 

Q31. Name three liquids, which when tested in the manner shown in Figure, may cause the magnetic needle to deflect.


Image from NCERT

 


Last modified: Sunday, 8 September 2019, 5:24 PM