1)An LED connected in series with a resistor to a 5V supply. Calculate the resistance of the series resistor required to give a current in the LED of 12 mA and a voltage across it of 2 V?
2)A potential divider has a total resistance of 1 kiloohms and carries a current of 3mA. What is the output p.d. if the sliding contact id at its centre point?
3a)A 9 volt battery has an internal resistance of 12 ohms.
What is the potential difference across its terminals when it is supplying a current of 50mA.
b)what is the maximum current which the battery could supply?
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