10 questions · Form 2 Science Bab 7: Electricity and Magnetism
Which rule is applied to determine the direction of the magnetic field around a straight current-carrying wire?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Which rule is applied to determine the direction of the magnetic field around a straight current-carrying wire?
Answer: B
The Right-Hand Grip Rule determines magnetic field direction: pointing the thumb in current flow direction causes fingers to curl in magnetic field direction.
2. In a series circuit containing three identical 3 Ω resistors, what is the total effective resistance?
Answer: D
In a series circuit, total resistance R_total = R1 + R2 + R3 = 3 Ω + 3 Ω + 3 Ω = 9 Ω.
3. When rubbing an ebonite rod with woolen cloth, the ebonite rod becomes negatively charged. What happened during rubbing?
Answer: B
Friction causes electrons to move from the woolen cloth onto the ebonite rod, giving the ebonite rod an excess negative charge.
4. Three identical 6 Ω resistors are connected in parallel across a battery. What is the effective total resistance of this parallel combination?
Answer: A
1R_total = 16 + 16 + 16 = 36 = 12. Therefore, R_total = 2 Ω.
5. What electrostatic hazard is prevented by attaching heavy metallic earthing chains to fuel tanker trucks?
Answer: B
Friction between fuel and pipes/air builds static electricity; grounding chains continuously discharge charges safely to the ground to prevent explosive sparks.
6. Why are copper wires widely used in electrical domestic circuits?
Answer: B
Copper has low electrical resistance and high conductivity, allowing electric current to flow efficiently with minimal energy loss as heat.
7. In a series circuit, how does potential difference (V) distribute across two lightbulbs with resistances of 2 Ω and 4 Ω?
Answer: B
In series circuits, total voltage divides proportionally across resistors (V = IR); higher resistance receives a larger share of voltage.
8. An electric circuit powered by a 12 V battery draws a current of 2 A. According to Ohm's Law (V = IR), what is the total resistance of the circuit?
Answer: A
Resistance R = VI = 12 V2 A = 6 Ω.
9. An uncharged object becomes negatively charged when it undergoes which process?
Answer: B
Gaining additional electrons creates an excess of negative charge over positive protons, giving the object a net negative charge.
10. What happens to the remaining light bulbs in a household parallel circuit if one light bulb burns out?
Answer: B
In parallel circuits, each branch operates on an independent electrical path; a broken branch does not interrupt current flow through other branches.