There is a potential difference of 3.6 V across the lamp in Figure 11.
The current through the lamp is 0.80 A.
Calculate the resistance of the lamp.
How to approach this question
1. Start with the equation V = I × R.
2. Rearrange the equation to make resistance (R) the subject.
3. Identify the values given: Potential difference (V) = 3.6 V and Current (I) = 0.80 A.
4. Substitute these values into your rearranged equation.
5. Calculate the resistance. The unit is Ohms (Ω).
Full Answer
We use Ohm's Law, which links potential difference (V), current (I), and resistance (R):
V = I × R
To find the resistance, we need to rearrange the equation by dividing both sides by current (I):
R = V / I
Now, substitute the given values:
- V = 3.6 V
- I = 0.80 A
R = 3.6 / 0.80
R = 4.5 Ω
Common mistakes
✗ Incorrectly rearranging the equation (e.g., multiplying V and I).
✗ Dividing current by voltage instead of voltage by current.
✗ Calculation errors.
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