A Level Physics Practice Exam

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Study for the A Level Physics Exam efficiently with engaging quizzes and multiple-choice questions designed to enhance your understanding. Prepare yourself for the challenges of A Level Physics!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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As current increases, what effect does it have on terminal voltage?

It increases the terminal voltage
It reduces the terminal voltage
It has no effect on terminal voltage
It doubles the terminal voltage

The correct answer is: It reduces the terminal voltage

The relationship between current and terminal voltage is influenced by the internal resistance of a power source, such as a battery. As the current increases, the voltage drop across the internal resistance also increases due to Ohm's law (V = IR), where I is the current and R is the internal resistance. This voltage drop reduces the terminal voltage available at the terminals of the power source. Therefore, as current flows more intensely through the internal resistance, the effective voltage that can be measured at the terminals diminishes, leading to a reduction in terminal voltage. This phenomenon is fundamental to understanding how real power sources behave under load, distinguishing them from ideal sources that maintain constant voltage regardless of current draw.