Question

12th std
Ch. current electricity


Plz ans this question ​

Answer 1

SoluTion :-

Emf of the storage battery (E) = 8.0 V

Internal resistance of the battery (r) = 0.5 Ω

DC supply voltage, V = 120 V

Resistance of the resistor (R) = 15.5 Ω

Effective voltage in the circuit = V¹

V¹ = V - E

V¹ = 120 - 8 = 112 V

Current flowing in the circuit = I

$\sf {I = \frac{V^{1}}{R+r} }\\\\\\\sf {\frac{112}{15.5+5} = \frac{112}{16} }\\\\\\\sf {=7A}$

Voltage across resistor R = IR = 7 × 15.5 = 108.5 V

DC supply voltage = Terminal voltage of battery + Voltage drop across R

Terminal voltage of battery = 120 - 108.5 = 11.5 V

Since a series resistor in the charging circuit limits the current drawn from the external source, the current will be extremely high and dangerous in its absence.