Define power of a lens. For what type of lens is it positive?

i. In a household electric circuit different appliances are connected in parallel to one another. Give two reasons.

ii. An electrician puts a fuse of rating 5A in that part of domestic electrical circuit in which an electrical heater of rating 1.5 kW, 220 V is operating. What is likely to happen in this case and why? What change, if any, needs to be made?

For which position of the object does a convex lens form a virtual and erect image? Explain with the help of a ray diagram.