Electricity — Numerical Practice

Grade 10 Science — Electricity — Numerical Practice: 25 practice questions with instant scoring and explanations.

1. Calculate current using Ohm's law: V = 12 V, R = 4 Ω. I =?
2. Two resistors 6 Ω and 3 Ω are in series. Total resistance is:
3. Two resistors 6 Ω and 3 Ω are in parallel. Total resistance is:
4. Calculate power: V = 10 V, I = 2 A. P =?
5. Electrical energy consumed: P = 100 W, time = 5 hours. Energy =?
6. Calculate heat produced using H = I²Rt: I = 2 A, R = 5 Ω, t = 10 s.
7. Monthly electricity bill: 5 units consumed, rate Rs 6/unit. Bill =?
8. Resistance formula: R = ρL/A. If L doubles, R becomes:
9. Three resistors 2 Ω, 3 Ω, 6 Ω in parallel. Total R =?
10. If resistivity ρ = 1.7 × 10⁻⁸ Ω·m, length L = 1 m, area A = 1 mm². R =?
11. Current through a conductor: I = V/R. If V = 20 V, R = 5 Ω. I =?
12. Power dissipated: P = V²/R. V = 15 V, R = 9 Ω. P =?
13. Resistance of two 10 Ω resistors in series is:
14. Heat generated in 5 seconds: H = I²Rt, I = 3 A, R = 10 Ω. H =?
15. Unit of electrical energy is:
16. For a 60 W bulb used for 10 hours, energy consumed =?
17. Conductance G = 1/R. If R = 4 Ω, then G =?
18. Temperature coefficient of resistance α. If ΔT = 50 K, ΔR/R₀ =?
19. Two 8 Ω resistors in parallel have equivalent resistance:
20. Calculate voltage: I = 5 A, R = 8 Ω. V =?
21. Annual electricity consumption: 100 units, rate Rs 8/unit. Cost =?
22. Power factor cos φ = 0.8. Real power if apparent power is 100 VA =?
23. Joule's heat law: H = I²Rt. If I doubles, H becomes:
24. Equivalent resistance of 4 Ω, 6 Ω in parallel =?
25. An appliance rated 2000 W, 240 V operates for 2 hours. Energy =?