PHYSCS FORM TWO
REVIEW QUESTIONS
23. JANET took a positively charged rod and brought near to body A and B. If body A is at a distance of 1cm and body B is at a distance of 3cm, which of the two bodies will be attracted more? give reason
⮚ Body A will be attracted more than body B
Reason
This is because electrostatic force decreases as the between charged bodies increases
31. When you run comb through dry air, it attracts bits of paper. Why? What would you expect if the hair is wet or if it a rainy day?
⮚ The comb gets charged due to friction thus it attracts bits of paper.
If it is wet or rain day friction is reduced hence comb less charged and cannot attract bits of paper
48. Why do you think cracking sound is heard while taking off nylon clothes?
⮚ Due to friction, nylon develops static charges (electrons) on them. These charges move in streams between nylon and our body (i.e. electric discharge takes place). This result in cracking sound and sparks of lightning
50. After lesson on electric field sir of physics left an exercise to the student. The drawing of one student was as shown here under :
Identify the mistake made by student in her drawing
Answer
⮚ The mistake is that field line has intersect since we know that field line never intersect
54. After walking across a carpeted floor you sometimes get a mild electric shock when you touch a metal door knob. Explain how this happens.
As you walk across a carpet your feet rub electrons off the carpet, leaving you with slightly negative static charge. When you reach for a doorknob you get a shock as electrons jump from you to the knob, which conducts electricity. OR
While walking on a carpet, you are sort of insulated hence high electrons accumulation. On the other hand, the door has excess of the opposite charges. This results in a mild electric shock.