Given,
EMF of battery,
Internal resistance of battery, r=
Current flowing in the circuit, I= 0.5 A
Using the forlmula
or
where, R is the external resistance.
is the required resistance.
Terminal voltage,
Given,
Resistance of the element,
Resistance of heating element at room temperature,
Temperature coeffient of the material of resistor, = 1.70 x 10–4 °C–1
Now, using the relation
we get,
is the required temperature of the element.