For a constant voltage, how is the resistance related to the current?

A. Resistance is inversely proportional to current, so when the resistance doubles, the current is cut in half.
B. Resistance is directly proportional to current, so when the resistance doubles, the current is cut in half.
C. Resistance is inversely proportional to current, so when the resistance doubles, the current doubles.
D. Resistance is directly proportional to current, so when the resistance doubles, the current doubles.



Answer :

Let's explore the relationship between resistance (R) and current (I) when the voltage (V) is kept constant using Ohm's Law. Ohm's Law is given by:

[tex]\[ V = I \times R \][/tex]

From Ohm’s Law, we can rearrange the formula to express current as:

[tex]\[ I = \frac{V}{R} \][/tex]

Here’s a detailed step-by-step explanation to understand the relationship:

1. Define Initial Conditions:
- Let’s consider a constant voltage [tex]\( V = 10 \)[/tex] volts.
- Let the initial resistance [tex]\( R_1 = 5 \)[/tex] ohms.

2. Calculate Initial Current:
- Using Ohm’s Law:
[tex]\[ I_1 = \frac{V}{R_1} \][/tex]
Substituting the values:
[tex]\[ I_1 = \frac{10}{5} = 2.0 \][/tex] amperes.

3. Double the Resistance:
- Now, we double the initial resistance:
[tex]\[ R_2 = 2 \times R_1 = 2 \times 5 = 10 \][/tex] ohms.

4. Calculate New Current with Doubled Resistance:
- Using Ohm’s Law again for the new resistance:
[tex]\[ I_2 = \frac{V}{R_2} \][/tex]
Substituting the values:
[tex]\[ I_2 = \frac{10}{10} = 1.0 \][/tex] ampere.

So, let's summarize the findings:
- Initially, with a resistance of 5 ohms, the current was 2.0 amperes.
- After doubling the resistance to 10 ohms, the current decreases to 1.0 ampere.

Thus, we can conclude:
- For a constant voltage, resistance is inversely proportional to current. When the resistance doubles, the current is cut in half.

Given the answer choices:
1. "Resistance is inversely proportional to current, so when the resistance doubles, the current is cut in half."

This statement is correct.