⚛️ Physics CBQ

u = -10cm, m = -3 (real image) m = -v/u → v = -30cm Mirror formula: 1/f = 1/v + 1/u 1/f = -1/30 - 1/10 = -4/30 f = -7.5 cm ✓

(a) v² = u² - 2gh 0 = 400 - 20h → h = 20 m (b) v = u - gt 0 = 20 - 10t → t = 2 s (c) Total = 2 × 2 = 4 s ✓

Parallel: 1/Rp = 1/4 + 1/6 = 5/12 Rp = 2.4 Ω Total: R = 2.4 + 5 = 7.4 Ω Current: I = V/R = 12/7.4 = 1.62 A ✓

Fleming's LHR: • Forefinger → Field (B) • Middle finger → Current (I) • Thumb → Force (F) Given: Current N→S, Field E→W Force = Vertically UPWARD ✓

f = +15cm, u = -20cm 1/v - 1/u = 1/f 1/v = 1/15 + 1/20 = 7/60 v = +60 cm m = v/u = -3 (inverted, magnified) Image: Real, Inverted, 3× ✓

(a) I = V/R = 220/44 = 5 A (b) P = VI = 220×5 = 1100 W (c) E = Pt = 1100×2 = 2200 Wh = 2.2 kWh (units) ✓