Question

What voltage must be applied to a 6.4-ohm lamp filament to develop 20 amperes of current?

Answer 1

We are asked to find the voltage that must be applied to a 6.4 ohm lamp filament to develop a current of 20 amperes.

Recall that Ohm's law is given by

`V=IR`

Where V is the voltage, I is current, and R is the resistance.

Substitute the given values

`\begin{gathered} V=20*6.4 \\ V=128\; \text{volts} \end{gathered}`

Therefore, a voltage of 128 volts must be applied.