Grade 8 Physics Questions and Answers
A free sample of Grade 8 Physics practice questions with the correct answer and an explanation, following the Lebanese curriculum. Useful for revision before school tests.
أسئلة الفيزياء للصف 8 مع الأجوبة والشرح وفق المنهج اللبناني.
How to use this page: read each question, try to answer it yourself, then open the answer to check your reasoning. Questions are grouped by the chapter they belong to on EduRise, in the order of the Lebanese Grade 8 Physics programme.
15 Grade 8 Physics practice questions
Chapter: DC Voltage · easy
1. What is the voltage of three 1.5 V cells connected in series (+ to −)?
- A. 1.5 V
- B. 4.5 V
- C. 3 V
- D. 0.5 V
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Answer: 4.5 V
Explanation: Voltages add in series.
Chapter: DC Voltage · easy
2. A power line is at 5 kV. Express it in volts.
- A. 500
- B. 5000
- C. 50
- D. 5000000
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Answer: 5000
Explanation: 1 kV = 1 000 V → 5000 V.
Chapter: Alternating Voltage · easy
3. Oscilloscope sensitivity 1 V per division; the peak of the wave is 4 divisions above the middle line. Maximum voltage?
- A. 3.5
- B. 4.5
- C. 5
- D. 4
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Answer: 4
Explanation: U_max = 4 × 1 = 4 V.
Chapter: Alternating Voltage · easy
4. What is the period of an alternating voltage?
- A. the number of cycles per second
- B. the height of the wave
- C. the duration of one complete cycle
- D. the maximum voltage
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Answer: the duration of one complete cycle
Explanation: Measured in seconds.
Chapter: The Voltage of the Mains · easy
5. In a correct installation, what is the effective voltage between the live wire and the neutral wire?
- A. 220
- B. 0
- C. 310
- D. 110
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Answer: 220
Explanation: The live wire is at 220 V with respect to the ground and the neutral.
Chapter: The Voltage of the Mains · easy
6. In a correct installation, what is the effective voltage between the live wire and the earth wire?
- A. 110
- B. 310
- C. 0
- D. 220
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Answer: 220
Explanation: The live wire is at 220 V with respect to the ground and the neutral.
Chapter: Resistors · easy
7. What is the meaning of "milliampere"?
- A. 1 mA = 0.001 A
- B. the flow of electric charge through a component, measured in amperes with an ammeter in series
- C. the property of a component that opposes the passage of current, measured in ohms
- D. the possible deviation of the real value from the marked value (gold ±5 %, silver ±10 %)
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Answer: 1 mA = 0.001 A
Explanation: Milliampere: 1 mA = 0.001 A
Chapter: Resistors · easy
8. Resistors of 120 Ω and 20 Ω are connected in series. Equivalent resistance?
- A. 17
- B. 2400
- C. 100
- D. 140
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Answer: 140
Explanation: R = R₁ + R₂ = 120 + 20 = 140 Ω.
Chapter: Electric Power and Energy · easy
9. A 10 W lamp is on for 10 s. Energy consumed in joules?
- A. 6000
- B. 20
- C. 100
- D. 1
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Answer: 100
Explanation: E = P × t = 10 × 10 = 100 J.
Chapter: Electric Power and Energy · easy
10. Which term matches this definition: "the heating of a conductor by the current, with power P = R × I²"?
- A. nominal power
- B. Joule effect
- C. standby
- D. kilowatt-hour
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Answer: Joule effect
Explanation: Joule effect: the heating of a conductor by the current, with power P = R × I²
Chapter: Mechanical Actions · easy
11. A dynamometer reads 30 N with a schoolbag hanging from it. Mass of the object (g = 10 N/kg, a constant number)?
- A. 6
- B. 3
- C. 2.5
- D. 1
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Answer: 3
Explanation: m = W / g = 30 / 10 = 3 kg.
Chapter: Mechanical Actions · easy
12. A brick has a mass of 2 kg. Its weight (g = 10 N/kg, a constant number)?
- A. 200
- B. 25
- C. 2
- D. 20
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Answer: 20
Explanation: W = m × g = 2 × 10 = 20 N (g is a constant number, g = 10 N/kg).
Chapter: Equilibrium of a Body · easy
13. What is the meaning of "load"?
- A. the force applied to a lever to move the load
- B. the distance from the pivot to the line of action of a force
- C. the object a lever lifts or the resisting force it overcomes
- D. the state of a body at rest whose forces balance each other
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Answer: the object a lever lifts or the resisting force it overcomes
Explanation: Load: the object a lever lifts or the resisting force it overcomes
Chapter: Equilibrium of a Body · easy
14. A 5 kg box rests on the floor. Reaction of the floor on the box (g = 10 N/kg, a constant number)?
- A. 100
- B. 0
- C. 50
- D. 5
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Answer: 50
Explanation: R = W = 50 N, vertical, upwards.
Chapter: Pressure in Liquids · easy
15. Which term matches this definition: "the horizontal top surface of a liquid at rest"?
- A. pascal
- B. free surface
- C. water tower
- D. density (mass per volume)
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Answer: free surface
Explanation: Free surface: the horizontal top surface of a liquid at rest
More practice
These are sample questions only. The full Grade 8 Physics course on EduRise includes every chapter, lessons, 1,556 questions and timed exams.
Physics questions in other grades
Other Grade 8 subjects
See also: Grade 8 Physics chapters · All question pages · Study guides
About these questions
Where do these Grade 8 Physics questions come from?
They are a sample from EduRise's Grade 8 Physics question bank (1,556 questions across 15 chapters), written to follow the Lebanese curriculum. Each chapter on EduRise has its own practice set and a timed exam.
Are the answers explained?
Yes. Every question on EduRise shows the correct answer and an explanation after you answer, in practice mode and in the exam review.
How do I get the full question bank?
Register at edurise.me and subscribe ($10/month) to practise every chapter of Grade 8 Physics, take the timed exams and track your progress.
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