Q. 105.0( 3 Votes )
Define principal focus of concave and convex mirror.
(i) The principal focus of a concave mirror is a point on its principal axis to which all the light rays, which are parallel and close to the axis, converge after reflection from the concave mirror.
(ii) A concave mirror has real focus.
Principal focus of a convex mirror
(i) The principal focus of a convex mirror is a point on its principal axis from which
a beam of light rays, initially parallel to the axis, appear to diverge after being
reflected from the convex mirror.
(ii) A convex mirror has virtual focus.
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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?Xam idea - Science