The transformer in another battery charger has a primary coil and a secondary coil - Edexcel - GCSE Physics Combined Science - Question 4 - 2020 - Paper 1

Given:

• Secondary voltage = 15 V
• Secondary current = 3.1 A
• Primary voltage = 230 V

Substituting the values into the equation:

ext{primary current} = rac{ ext{secondary voltage} imes ext{secondary current}}{ ext{primary voltage}} = rac{15 imes 3.1}{230}

Calculating the numerator:

$$15 imes 3.1 = 46.5$$

Now substituting back into the equation to find the primary current:

ext{primary current} = rac{46.5}{230} ominal ext{A} \ ext{primary current} ext{ (approximately)} = 0.2022 ext{ A}

Therefore, the current in the primary coil is approximately 0.202 A.