Bihar Board Class 10 Science: Electricity
Full-Length Test (30 Marks)

Section A: MCQ (1 mark each, 8 questions)

1. The SI unit of electric charge is:

A) Ampere B) Coulomb C) Volt D) Ohm

2. The instrument used to measure electric current is:

A) Voltmeter B) Ammeter C) Galvanometer D) Potentiometer

3. Ohm’s Law is represented by the equation:

A) V = IR B) V = I/R C) V = I+R D) V = IR²

4. If the resistance in a circuit is doubled, the current will:

A) Double B) Become half C) Remain same D) Increase four times

5. When resistors are connected in series, the total resistance is:

A) Less than the smallest resistor B) Equal to the largest resistor C) The sum of all resistors D) Zero

6. Two resistors of 6 Ω and 12 Ω are connected in parallel. Their equivalent resistance is:

A) 18 Ω B) 9 Ω C) 4 Ω D) 3 Ω

7. The power consumed by a device is 60 W when operated at 120 V. The current drawn is:

A) 0.5 A B) 2 A C) 1 A D) 0.25 A

8. Which of the following is not an effect of electric current?

A) Magnetic effect B) Chemical effect C) Heating effect D) Gravitational effect

Section B: Short Answer (2 marks each, 5 questions)

9. Define electric potential difference.

10. State Ohm’s Law.

11. What happens to the total resistance when more resistors are added in parallel?

12. Write the formula for electrical power and define each term.

13. Name one device that works on the heating effect of electric current.

Section C: Long/Numerical Answer (4 marks each, 3 questions)

14. Calculate the resistance of a wire if 0.5 A current flows through it when a potential difference of 3 V is applied.

15. An electric iron of resistance 20 Ω draws a current of 5 A. Calculate the heat produced in 30 seconds.

16. Explain the heating effect of electric current with an example and its application in daily life.

Answer Key

• 1. B) Coulomb
• 2. B) Ammeter
• 3. A) V = IR
• 4. B) Become half
• 5. C) The sum of all resistors
• 6. D) 4 Ω
  Explanation: 1/R = 1/6 + 1/12 = (2+1)/12 = 3/12 ⇒ R = 4 Ω
• 7. A) 0.5 A
  Explanation: I = P/V = 60/120 = 0.5 A
• 8. D) Gravitational effect
• 9. Electric potential difference is the work done to move a unit charge from one point to another. (V = W/Q)
• 10. The current through a conductor is directly proportional to the voltage across it, provided temperature remains constant. (V = IR)
• 11. Total resistance decreases when more resistors are added in parallel.
• 12. P = VI, where P = Power, V = Voltage, I = Current
• 13. Electric iron (or heater, toaster, bulb, etc.)
• 14. R = V/I = 3/0.5 = 6 Ω
• 15. H = I²Rt = (5)² × 20 × 30 = 25 × 20 × 30 = 15000 J
• 16. When current passes through a resistor, it produces heat (heating effect). Example: Electric iron, which uses this effect to press clothes.

Performance Analysis