You are given 2 fuse wires A and B with current ratings 2 A and 5 A, respectively. Justify with reason which of the two would you use with a 1000 W, 220 V room heater?

Given,

• Current rating of the fuse wire A ($\text I_\text A$) = 2 A
• Current rating of the fuse wire B ($\text I_\text B$) = 5 A
• Power rating of the heater (P) = 1000 W
• Voltage rating of the heater (V) = 220 V

Then,

Current drawn by the heater (I) is given by,

$\text I = \dfrac{\text P}{\text V} = \dfrac{1000}{220} \approx$ 4.54 A

Here,

$\text I \gt \text I$\text A and $\text I \lt \text I\text B$

Thus,

A fuse should have a rating just above the normal working current. As 2 A fuse would melt during normal use, cutting off the supply but 5 A fuse will allow the heater to operate normally and will blow only if the current exceeds about 5 A, protecting the circuit from overload.

Hence, fuse wire B with current rating 5 A should be used with the heater.