Question

A soldering rod draws an energy of 86400 J in 8 min when the current flowing through its element is 6 A. The resistance of the heating element of the soldering rod is:

Options

• 5 Ω

• 5.5 Ω

• 4.5 Ω

• 6 Ω

Answer 1

5 Ω

Explanation:

Convert 8 min to 480 s.

$$W = I^2Rt$$

$$R = \frac{W}{I^2t}$$

$$= \frac{86400}{6^2 \times 480}$$

$$= 5\ \Omega$$