How can the voltage change in relation to current if the resistance is constant. This is suppose to be using Ohm's law.

see above.

According to Ohm's law, the relationship between voltage (V), current (I), and resistance (R) can be expressed as V = I * R. If the resistance is kept constant, then any change in current will result in a proportional change in voltage.

To understand this concept further, let's consider an example. Suppose we have a circuit with a constant resistance of 10 ohms. If we pass a current of 2 amperes through this circuit, the voltage across the resistance can be calculated by multiplying the current (I) with the resistance (R), so V = 2 A * 10 Ω = 20 V.

Now, let's say we increase the current to 4 amperes while keeping the resistance constant. Applying Ohm's law again, we calculate the new voltage as V = 4 A * 10 Ω = 40 V. As you can see, as the current doubled, the voltage also doubled because the resistance remained the same.

Therefore, when the resistance is constant according to Ohm's law, the voltage across a circuit will change in direct proportion to any changes in the current flowing through the circuit.