Question

A 100 watt lamp has a resistance of 120 Ω. Find the current in the lamp.Group of answer choices2.15 A1.20 A0.913 A0.833 A

Answer 1

0.913 A

Explanation

the poweris given by

$P=I^2R$

so

Step 1

Let

$\begin{gathered} I=I \\ P=100\text{ watts} \\ \text{resistance}=120\text{ ohm} \end{gathered}$

b) now replace

$\begin{gathered} P=I^2R \\ 100=I^2\cdot120 \\ \text{divide boths sides by 120} \\ \frac{100}{120}=\frac{I^2\cdot120}{120} \\ 0.8333=I^2 \\ \text{square root in both sides} \\ \sqrt{0.8333}=\sqrt{I^2} \\ 0.91287=I \\ \text{rounded} \\ I=0.913\text{ Amperes} \end{gathered}$

therefore, the answeris

0.913 A

I hope this helps you