A heating element is marked 210V, 630W. Find the resistance of the element when connected to a 210V dc source.
Given: A heating element is marked 210V,630W
To find the resistance of the element when connected to a 210V dc source.
Solution:
The power of the heating element is 630 Watt and its voltage is 210V. Thus, the current drawn can be calculated with the formula
P=VI,
where P denotes the power, V stands for the voltage and I is the symbol of the current.
So the value of the current drawn =PV=630210=3A
And the resistance of the element when connected to a 210V dc source = VI=2103=70Ω