Understanding how electric charges behave can be confusing, especially when it comes to objects in contact or near charged bodies. Here’s a Secondary 4 question on Static Electricity that has puzzled many students:
Question:
Three initially uncharged spheres X, Y and Z are in contact, each supported on an insulating stand. A positively charged rod is placed close to but not touching X.
Which of the following best illustrates the distribution of charges on sphere Y?
This type of question on Static Electricity is common in Singapore Secondary Science exams and often leads to misconceptions about how charges are induced and redistributed. Students may struggle to visualise the interaction between neutral objects and charged rods, especially when the question involves grounding or movement, which make students easily confused.
To truly grasp this concept, students need more than memorisation. They need to reason through how electric charges interact in different setups. That is how the learning platform nurtures confident and self-motivated learners, with on-demand homework help offering timely support when it matters most.
Ben
- Hello
- Hi
- Can u explain why Y has no charges ?
- Sure.
- So first thing you need to understand
- When the 3 spheres are put together, charges can move within. Charges I’m referring to the negative charges.
- But the positive charges cannot move right
- So when the positive charged rod is brought near to the LHS of the sphere, the negative charges in the 3 spheres all move towards the sphere on the left.
- Yes, you are right
- Then how come Y has no positive or negative
- I think the diagram is not illustrating it has no charge. Rather it is showing that the number of positive and negative charges even out each other
- That’s why it is neutral in charge
- Ohh
- So the number of charges on the left and right side of Y are equal ?
- Not exactly
- Rather cos Y is in the middle, that is where it forms this neutral space, where the charges are sort of evenly distributed within the sphere
- Is like a magnet
- If the LHS is North Pole, the RHS is South Pole
- The middle of the magnet has no polarity, it is sort of neutral in charge.
- Ahh i see
- Okay thank you
- ?
