Question

Find the reading of ammeter when key is off and on.

Answer 1

when switch is off reading is 0 amperes as no current is flowing.....

when switch is on...

resistance will be :

$\frac{1}{8} + \frac{1}{4} + \frac{1}{2}$

$\frac{1 + 2 + 4}{8}$

$\frac{7}{8}$

thus, resistance will be 8/7 ohm

voltage is 9v....by ohms law,

$9 = i \frac{8}{7}$

$\frac{63}{8} = i$

ammeter reading will be 7.8 amperes