Chapter-4 Electricity — Online MCQ Test
SCIENCE · Grade 8 · CBSE(NCERT)
Practice Chapter-4 Electricity with a free chapter-wise online MCQ test.
This chapter covers: electric current - heating effect - magnetic effect - electromagnet - fuse - electric circuit - resistance.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-4 Electricity — Important Questions & Answers
What is electric current?
- A. The flow of electrons through a conductor
- B. The amount of charge flowing per unit time
- C. The resistance in a circuit
- D. The voltage across a conductor
Answer: B. The amount of charge flowing per unit time
Electric current is defined as the amount of electric charge flowing through a cross-section of a conductor per unit time.
Electric current is defined as the amount of electric charge flowing through a cross-section of a conductor per unit time.
Which unit is used to measure electric current?
- A. Volt
- B. Ampere
- C. Ohm
- D. Watt
Answer: B. Ampere
Electric current is measured in Amperes (A), named after physicist André-Marie Ampère.
Electric current is measured in Amperes (A), named after physicist André-Marie Ampère.
Which of the following is NOT a component of an electric circuit?
- A. Power source
- B. Conductor
- C. Magnetic field
- D. Switch
Answer: C. Magnetic field
A basic electric circuit requires a power source, conductors, and a switch, but a magnetic field is not a necessary component of the circuit itself.
A basic electric circuit requires a power source, conductors, and a switch, but a magnetic field is not a necessary component of the circuit itself.
An electric bell works on the principle of:
- A. Heating effect of current
- B. Magnetic effect of current
- C. Chemical effect of current
- D. Light emission
Answer: B. Magnetic effect of current
An electric bell uses the magnetic effect of electric current. The electromagnet attracts the armature to produce a ringing sound.
An electric bell uses the magnetic effect of electric current. The electromagnet attracts the armature to produce a ringing sound.
In a circuit, if voltage is doubled while resistance remains constant, what happens to the current?
- A. Current is halved
- B. Current doubles
- C. Current remains the same
- D. Current becomes zero
Answer: B. Current doubles
According to Ohm's law (V = IR), if voltage doubles and resistance is constant, current must double to maintain the equation.
According to Ohm's law (V = IR), if voltage doubles and resistance is constant, current must double to maintain the equation.