# Practical resistors

### Explanation of question 6

A 68 resistor is in parallel with an 82 resistor. The combination is connected across a 6V supply. The rating of the 68 resistor and 82 resistor should be respectively

1. 1 W, 0.5 W
2. 1 W, 0.25W
3. 0.5W, 1 W
4. 0.5W, 0.5 W

The answer is :- 1 p.d. across each resistor is 6 V. Power dissipated is V2/R Thus power dissipated in the 68 resistor will be 36/68W = 0.53W. power dissipated in 82 resistor will be 36/82W = 0.44W. A resistor should be chosen such that it's power rating is higher than that which will be required in use. Thus a 1W resistor would be used for the 68 resistor, and a 0.5W resistor would be used for the 82 resistor.

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