Circuit 9 H (SS Network of Bulbs Suppose that we want to make bulb H dimmer than
ID: 1548551 • Letter: C
Question
Circuit 9 H (SS Network of Bulbs Suppose that we want to make bulb H dimmer than it was in circuit 9 (when 1 glow flowed through it). What will we need to do to the flow through H I1 In circuit 9, suppose that the obstacle presented by the rheostat and the obstacle presented by bulb Hare both of size L) For the sake of being definite, suppose that 1 glow is flowing. If the obstacle presented by the rheostat is doubled then the flow from the battery will decrease Will the flow decrease to less than half of what it was or to more than half of what it was? Explain. 121 What will happen to the pressure difference across the rheostat? Explain. 131 Hint: calculate the pressure difference across the rheostat before and after the rheostat changes. Be sure to use the correct obstacle and flow when doing this What will happen to the pressure difference across bulb H? Explain. 12l What will this do to the brightness of bulb H? Explain. IijExplanation / Answer
1) We need to reduce the flow
2) Let resistance of bulb and rheostat be r
Net resistance = 2r
When resistance of rheostat is doubled
net resistance = 3r
Since change in resistance is 1.5 times so flow will reduce to more than half of it was
3) V = IR
V' = 2/3I*2R = 4/3IR= 4/3V
Hence pressure difference increases
4) Since pressure difference across rheostat has incresed it will reduce across the bulb.
5) make it dimmer as Brightness is directly proportional to voltage across it.