Question

Question 28 (ii)
$B_1,B_2,and{B}_3$ are three identical bulbs connected as shown in figure. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.
(ii) What happens to the reading of $A_1,A_2{A}_3$ and A when the bulb $B_2$ gets fused?

Answer 1

(ii) $A_2$ - Zero
Total resistance can be found out by the ratio of total resistance and total current(When all bulbs glow)
$Totalresistance=\frac{4.5}{3}=1.5$
Therefore, total current = $\frac{4.5}{2.25}=2A$
Since bulb 1 and bulb 3 are identical, 1 A of current will flow through each.
$A_1$ shows 1 ampere, $A_2$ shows zero, $A_3$ shows 1 ampere and A shows 2 amperes.