Q. 283.8( 21 Votes )
B1, B2 and B3 are three identical bulbs connected as shown in Figure 12.8. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.
(i) What happens to the glow of the other two bulbs when the
bulb B1 gets fused?
(ii) What happens to the reading of A1, A2, A3 and A when the
bulb B2 gets fused?
(iii) How much power is dissipated in the circuit when all the
three bulbs glow together?
(i) There will be no effect on glow of other two bulbs and will remain same when B1 gets fused because glowing of bulb depends on power and the potential difference and resistance remains same of other two bulbs.
(ii) When there are parallel connections:
Net resistance will be 1/R = 1/R1+1/R2+1/R3
Since resistance is same so, R’ = R/3
Applying ohm’s law V= IR
Since B2 gets fused, so now only two bulbs B1 and B3 are in parallel
Therefore net resistance in parallel 1/R’ =2/R
R’ = 4.5/2 Ω
I = V/R’ = 2×4.5/4.5
I = 2A
So, current will be distributed in both the bulbs as 1 A each.
(iii) Power dissipated when all three bulbs glow together
P = V × I
P= 4.5 × 3 = 13.5 W
Rate this question :
Name two gases which are filled in filament type electric light bulbs.Lakhmir Singh & Manjit Kaur - Physics
Which effect of current is utilized in the working of an electric fuse?Lakhmir Singh & Manjit Kaur - Physics
Write down the formula for the heat produced when a current I is passed through a resistor R for time t.Lakhmir Singh & Manjit Kaur - Physics
Which effect of current is utilized in an electric light bulb?Lakhmir Singh & Manjit Kaur - Physics
A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination of resistances in half a minute.Lakhmir Singh & Manjit Kaur - Physics
The heat produced in a wire of resistance ‘x’ when a current ‘y’ flows through it in time ‘z’ is given by :Lakhmir Singh & Manjit Kaur - Physics
The current passing through a room heater has been halved. What will happen to the heat produced by it?Lakhmir Singh & Manjit Kaur - Physics
Which of the following is the most likely temperature of the filament of an electric light bulb when it is working on the normal 220 V supply line?Lakhmir Singh & Manjit Kaur - Physics
An electric fuse works on the:Lakhmir Singh & Manjit Kaur - Physics
The elements of electrical heating devices are usually made of:Lakhmir Singh & Manjit Kaur - Physics