Question

In norma use, a current of 3.5 A flows through a hair dryer. Choose a suitable fuse from the following
(a) 3 A
(b) 5 A
(c) 10 A
(d) 30 A

Answer 1

Answer:

B) 5A

Explanation:

Current rating = power/volt * 1.25

= normal current * 1.25

= 3.5*1.25

= 5A

Answer 2

The suitable fuse would be (b) 5 A.

Explanation:

• A fuse with current capacity greater than the current tired by the device must be used.
• We will select a fuse with the current rating 5A and if the current’s value surpasses 5 A, the fuse wire will liquify.
• Normally, current of 5 A can be handled by the hairdryer. The required fuse is 5A.
• Neither, 13 Amp fuse will be very high, whereas a 3-amp fuse is inadequate, which will ultimately blow with a current of 4 amps.  
• So, the Safety factor, is considered as 1.2, so the safe current will be $I = 4.3$ or $5$ Amp.