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16 Cards in this Set
- Front
- Back
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What is a series circuit? |
Components that are connected one after another on the same loop of the circuit are connected in series. The current that flows in each component connected in series is the same.
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The circuit diagram shows a circuit with two lamps connected in series. If one lamp breaks, what will happen to the other lamp?
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If one lamp breaks, the other lamp will not light. |
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What happens to the potential difference when the number of cells in a circuit is changed.
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A typical cell produces a potential difference of 1.5 V. When two or more cells are connected in series in a circuit, the total potential difference is the sum of their potential differences. For example, if two 1.5 V cells are connected in series in the same direction, the total potential difference is 3.0 V. |
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What happens to the current when the number of cells in a circuit is changed.
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When more cells are connected in series in a circuit, they produce a bigger potential difference across its components. More current flows through the components as a result.
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What would happen If two 1.5V cells are connected in series, but in opposite directions? |
If two 1.5 V cells are connected in series, but in opposite directions, the total potential difference is 0 V, so no current will flow.
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What happens when resistors are connected in series? |
When resistors are connected in series, the current through each resistor is the same. In other words, the current is the same at all points in a series circuit. The total potential difference across all the resistors is equal to the sum of the potential differences across each resistor. In other words, the potential differences around the circuit add up to the potential difference of the supply. The total resistance of a number of resistors in series is equal to the sum of all the individual resistances. RT = R1 + R2 + R3 |
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In a series circuit, the total p.d. is shared between all its components. The resistors in the figure all have the same current flowing through them. Calculate the p.d. across each resistor. |
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Draw a circuit with four identical cells in series that will give an output p.d. of 0 volts. |
Two cells face one way and two cells face the other way. |
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Draw a circuit with an 18 V battery made up of 3 V cells and two resistors in series.
One resistor is 200 Ω and the other is 400 Ω. Calculate the p.d.across each resistor. |
A series circuit with six cells all facing the same way; The 200 Ω resistor has 6 V and the 400 Ω resistor has 12 V. |
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Redraw the circuit in the figure with a third resistor in series of 5 Ω. Now calculate the p.d. across each resistor. |
10 Ωresistor has 1.7 V, 20 Ω resistor has 3.4 V and the 5 Ωresistor has 0.9 V. |
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If two 1500 Ω resistors were in series in a circuit with a 3 V supply, what current would pass through them? |
0.001 A. |
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In a torch there are four cells, each 1.5 V. One of the cells is put in the wrong way round. Describe what the effect of this would be in terms of p.d. supply, current and how well the torch would work. |
The voltage output from the cells would be 3 V rather than 6 V. The current would be about half what would normally flow although (higher grade level) the resistance of the filament lamp would be less as it would not get as hot, so more than half the normal current would flow. The bulb might glow but only dimly. |
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If a 200 Ω resistor is in a series circuit with a 10 V supply and another resistor, what resistance would the other resistor have to be if the current in the circuit is 0.02 A? |
300 Ω |
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A particular type of copper wire has a resistance of 34 Ω per kilometre. Calculate the resistance of a 50 cm length. |
0.017 Ω |
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Use drawings and written explanations to describe how resistances in a series circuit add together. |
The model needs to use a single current flow and show that the resistances build up on top of each other. |
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What are the key points to remember? |
Whencurrents join or split the smaller currents always add up to the same size asthe larger one. Iftwo components are connected in parallel, each will have the same p.d.across it. Thetotal resistance in a series circuit is the sum of the resistances of theindividual components. |
