Let’s go step by step to solve each question.
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Q1-a: What happens to the bulb if we turn the switch on?
Looking at the diagram:
- On the left, there’s an “Open Circuit” — the switch is OFF (not connected), so the bulb is OFF.
- On the right, there’s a “Closed Circuit” — the switch is ON (connected), and the bulb is lit up.
So, when you turn the switch
on, you complete the circuit. That means electricity can flow from the battery, through the wires, through the bulb, and back to the battery. When electricity flows through the bulb, it lights up.
✔ So, turning the switch on makes the bulb light up.
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Q1-b: In which circuit that electricity cannot flow? Explain why?
Again, look at the two diagrams:
- Left side: “Open Circuit” → switch is open (gap in the path) → no complete loop → electricity CANNOT flow.
- Right side: “Closed Circuit” → switch is closed (no gap) → complete loop → electricity CAN flow.
Electricity needs a full, unbroken path (a loop) to move. If there’s a break — like an open switch — electrons can’t jump across the gap. So, in the open circuit, electricity stops.
✔ Electricity cannot flow in the
open circuit because the switch is off, breaking the path. No complete loop = no current.
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Q2: Why do appliances have a plastic covered plug?
Look at the picture of the plug — the metal pins are inside or surrounded by plastic. The plastic part covers everything except the very tips of the pins.
Why?
- Metal conducts electricity — that’s good for carrying power into the appliance.
- But if your fingers touch live metal parts while plugging/unplugging, you could get shocked!
- Plastic does NOT conduct electricity — it’s an insulator.
- So, covering the plug with plastic keeps you safe from electric shock.
Also, plastic protects the metal pins from bending, rusting, or getting dirty.
✔ Appliances have plastic-covered plugs to keep users safe from electric shocks and to protect the metal parts.
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Final Answer:
Q1-a: The bulb lights up when the switch is turned on.
Q1-b: Electricity cannot flow in the open circuit because the switch is off, creating a break in the path — electricity needs a complete loop to flow.
Q2: Appliances have plastic-covered plugs to prevent electric shocks (since plastic doesn’t conduct electricity) and to protect the metal pins.
Parent Tip: Review the logic above to help your child master the concept of 4th grade science electricity worksheet.
