Warning: Undefined array key 1 in /home/acaproso/public_html/._System/._Template/.Main.php on line 118
Electromagnetism questions

Electromagnetism questions | form four Physics

Find Electromagnetism examination questions, form four Physics in acaproso.com

# Question
1

Describe the structure and mode of action of a simple d.c. motor.


Short answers
2

Draw a diagram of an electric bell showing the polarity of the electromagnet, the direction of the current, the core, the yoke, spring and the armature.


Short answers
3

Explain what will happen to the mode of action of the electric bell if the core and yoke are made of steel instead of soft iron.


Short answers
4

Which one is not a region of electromagnetic spectrum?

  1. Radio waves
  2. X-rays
  3. Infrared lights
  4. Ulltraviolet light
  5. Invisiblle light waves.

Multiple choices
5

Which of the following electromagnetic waves is used to detect flaws and defects in steel plates?

  1. infrared waves
  2. ultraviolet waves
  3. x­rays
  4. gamma rays
  5. micro waves.

Multiple choices
6

Carefully study Figure 2 which shows a design for an electrical operation model for lifting metal objects. Briefly explain three things you can do so that a heavier iron metal block can be lifted.

electromagnetism form four physics


Short answers
7

Electrical energy is distributed in all parts of Tanzania by the National grid system which transmits alternating current at a very high voltage. Explain why is it  necessary to have a very high voltage?


Short answers
8

A generator producing a varying current from 0 to 10 A was allowed to flow in a coil of magnetic field. After a time interval the current was observed to be 4 A. Describe how back e.m.f. Was induced in a self-induction.


Short answers
9

Match the items in ​ List A with responses in ​ List B ​ by writing the letter of the correct response beside the item number in the answer booklet provided.

LIST A LIST B
  1. Materials that can strongly be magnetized.
  2. Substance which are made up of soft iron.
  3. Materials that cannot be affected by magnets.
  4. Objects which are made up of steel.
  5. Groups of magnetic dipoles arranged themselves in a magnetized object.
  6. Field lines of force used for finding locations of different places.
  7. The process of aligning the domains of atoms in one direction.
  8. The process of destroying the alignment in a magnetized material.
  9. Materials that can redirect field lines of force.
  10. The region around a magnet in which magnetic materials are attracted.
  1. Paramagnetic
  2. Temporary magnets
  3. Zinc and Copper
  4. Permanent magnets
  5. Magnetic domains
  6. Earth’s magnetic field
  7. Induced magnetism
  8. Magnetization
  9. Demagnetization
  10. Permeable
  11. Neutral point
  12. Ferromagnetic
  13. Magnetic field

 


Matching items
10

Show how Lenz`s law is a special case of the law of conservation of energy.


Short answers