2. (a) Which of these symbols is used to represent a thermistor in an electrical circuit? A B C D (b) A student investigates how the current in a lamp changes with the potential difference across the lamp - Edexcel - GCSE Physics Combined Science - Question 2 - 2019 - Paper 1

To find the missing resistance value for the potential difference of 3.0 V and the associated current, we use Ohm's law, which states:

$V = I imes R$

Rearranging the formula gives:

$R = \frac{V}{I}$

a) Using the values from the table for 3.0 V, we can assess the current of 0.18 A.

Substituting in the values:

$R = \frac{3.0}{0.18} \approx 16.67 \Omega$

Thus, the missing value for resistance corresponding to a potential difference of 3.0 V and a current of 0.18 A is approximately 17 Ω.