tolong ya nomor 21 sama 22 pake cara makasih...

Listrik Dinamis - Transformator
Kelas IX

21.]
Tegangan tetap , sehingga
i₁ R₁ = i₂ R₂
2 × R = i₂ × 2R
i₂ = 1 A ⬅ Jawab [D]

22.]
Vₚ = 240 V
Vₛ = 12 V
Pₚ = 300 W
η = 50 %

iₛ = __ ?

η = (Pₛ / Pₚ) × 100%
50% = (Pₛ / 300) × 100%
½ = (Pₛ / 300)
Pₛ = 150 W

Pₛ = Vₛ iₛ
150 = 12 × iₛ
iₛ = 12,5 A [C]