Quick questions on DC circuits: Kirchhoff's laws, internal resistance and potential dividers - WJEC A-Level Physics

3short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What is the potential divider?

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A potential divider uses two resistors in series to provide a fraction of the supply voltage,

V_{\text{out}} = \dfrac{R_2}{R_1 + R_2}V_{\text{in}}

. Replacing one resistor with a thermistor or LDR makes the output respond to temperature or light.

What is q1?

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A cell of EMF

1.5\,\text{V}

and internal resistance

0.50\,\Omega

drives a current of

0.20\,\text{A}

. Find the terminal voltage. [2 marks]

What is q2?

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State Kirchhoff's first law and the conservation principle it expresses. [2 marks]

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