Select the correct answer.
Ian performs an experiment on an electric circuit. He increases the voltage from 25 volts to 50 volts while keeping the resistance constant. What will be the effect of doing this on the current?
A. The current will increase.
B. The current will decrease.
C. The current will stay constant.
D. The current will stop flowing.
Answer (1)
Ohm's Law states that V = I R , where V is voltage, I is current, and R is resistance.
Express current as I = R V .
The initial current is I 1 = R 25 and the final current is I 2 = R 50 .
The ratio of the final current to the initial current is I 1 I 2 = 25 50 = 2 , so the current will increase.
The current will increase. A
Explanation
Problem Analysis Let's analyze the problem. We are given that the voltage in an electric circuit is increased from 25 volts to 50 volts, while the resistance is kept constant. We need to determine the effect of this change on the current.
Ohm's Law Ohm's Law states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with the constant of proportionality being the resistance (R). Mathematically, this is expressed as: V = I R
Expressing Current We can rearrange Ohm's Law to express the current (I) in terms of voltage (V) and resistance (R): I = R V
Initial Current Let V 1 be the initial voltage and I 1 be the initial current. Then, I 1 = R V 1
Final Current Let V 2 be the final voltage and I 2 be the final current. Then, I 2 = R V 2
Comparing Currents We are given that V 1 = 25 volts and V 2 = 50 volts. The resistance R is constant. To find the effect on the current, we can compare the final current I 2 to the initial current I 1 by finding the ratio I 1 I 2 :
I 1 I 2 = R V 1 R V 2 = V 1 V 2
Calculating the Ratio Substituting the given values, we get: I 1 I 2 = 25 50 = 2
Conclusion Since the ratio I 1 I 2 = 2 , this means that I 2 = 2 I 1 . Therefore, the final current is twice the initial current. This indicates that the current will increase.
Examples
Understanding the relationship between voltage, current, and resistance is crucial in electrical engineering. For example, if you're designing a circuit for a device that requires a specific current to operate correctly, you need to carefully choose the voltage source and the resistance to achieve that current. If the voltage increases while the resistance remains constant, the current will increase proportionally, potentially damaging the device if the current exceeds its tolerance. This principle is also used in adjusting the brightness of a light bulb by varying the voltage applied to it.
