if the current is one half ampere when the resistance is 240 ohms, what is the current when the resistance is 540 ohms?

Assuming a constant voltage, then since

E = IR is constant,

(1.2)(240) = I(540)

Now it's easy to find the new current.

To find out the current when the resistance is 540 ohms, we can use Ohm's Law. Ohm's Law states that the current (I) flowing through a conductor is equal to the voltage (V) across the conductor divided by the resistance (R) of the conductor.

Mathematically, Ohm's Law can be expressed as:
I = V / R

In the given scenario, we know that the current (I) is 0.5 amperes (or 1/2 ampere) when the resistance (R) is 240 ohms.

Plugging these values into Ohm's Law, we can rearrange the formula to solve for the voltage (V):
V = I * R

Substituting the known values:
V = 0.5 A * 240 Ω
V = 120 volts

So, when the resistance is 240 ohms, the voltage across the conductor is 120 volts.

Now, to find the current when the resistance is 540 ohms, we can again use Ohm's Law. Since the voltage (V) remains the same (120 volts), we can substitute this and the new resistance (R) into the formula:

I = V / R
I = 120 V / 540 Ω
I ≈ 0.222 amperes (or 222 milliamperes)

Therefore, when the resistance is 540 ohms, the current is approximately 0.222 amperes (or 222 milliamperes).