IB myp 4-5 physics – Practice Questions- All Topics
Topic :Electromagnetism-Static Electricity
Topic :Electromagnetism– Weightage : 21 %
All Questions for Topic : Electric Fields,Static Electricity ,Magnetism,Magnetic Fields,Current,Power,Voltage,Electric Circuits,Electric and Magnetic Fields,Electromagnetic forces and induction
Question (8 marks)
Question a (1 mark)
Select an appropriate charge for each particle below.
Electron: ………..
Proton: …….
Neutron:……….
▶️Answer/Explanation
Ans:
Proton: Positive charge (+)
Neutron: No charge (neutral)
Question b (3 mark)
Most materials are electrically neutral; they contain equal numbers of charged particles. The animation shows that if a cloth is used to rub a plastic rod, the rod becomes positively charged.
Use the animation to explain the process that has occurred between the cloth and the rod, leaving the rod positively charged.
▶️Answer/Explanation
Ans:
When a cloth is used to rub a plastic rod, the process that occurs is known as “triboelectric charging” or “tribocharging.” This process involves the transfer of electrons between the cloth and the rod, resulting in the rod becoming positively charged.
In the animation, when the cloth rubs against the plastic rod, their surfaces come into contact and then separate. During this rubbing action, there is a transfer of electrons between the two materials. The atoms in the cloth have a greater affinity for electrons compared to the atoms in the plastic rod.
As the cloth rubs against the rod, some electrons from the atoms in the rod are transferred to the atoms in the cloth. This transfer of electrons leaves the plastic rod with a deficiency of electrons, resulting in an overall positive charge. At the same time, the cloth gains the extra electrons, acquiring an overall negative charge.
The rubbing action causes the surfaces of the materials to become charged due to the redistribution of electrons. The difference in the electron affinity between the cloth and the plastic rod leads to the plastic rod becoming positively charged, while the cloth becomes negatively charged.
This process of triboelectric charging demonstrates how friction can cause the transfer of charges between materials, resulting in one material acquiring a positive charge and the other material acquiring a negative charge.
Question:
You take off a polyester sweater in the dark and notice some sparks. Why does this not happen to the same extent with a woolen sweater?
▶️Answer/Explanation
Ans: Polyester can become negatively whereas wool becomes positively charged. This means that polyester can build up a surplus of electrons, which can easily be lost