# Malaysia SPM Form 5 Physics - Electromagnetism

1.1 Introduction to Magnetism
1.2Straight Wire and Coil
1.3 Solenoid
1.4 Uses of Electromagnet
2.1 Catapult Force
2.2 Application of Catapult Force
3.1 Electromagnetic Induction
3.2 DC and AC Generator
4.1 Transformer
4.2 Transformer - Calculation
5.1 Generation and Transmission of electricity

# Transformer

The SPM Physics Workbook is developed under the One-School.net Free Books Project. The content of this book is strictly follow Malaysia SPM (Sijil Pelajaran Malaysia) syllabus. The aim of this project is to provide a complete electronic supplementary network for students to develop self-learning skills by breaking the spoon-feed rituals and to encourage them to compile educational information from the Internet.
1. What is the suitable material to be used as the core and coil in a transformer?

 Core Coil Copper Soft iron Steel Copper Soft iron Copper Copper Steel

2. What are the relative numbers of turns on the two coils of a step-down transformer?

Number of turns of primary coil is more than number of turns of secondary coil.
Number of turns of primary coil is less than number of turns of secondary coil.
Number of turns of primary coil is equals to number of turns of secondary coil.

3. What is the function of a step-down transformer?
To raise up current
To lower down current
To raise up potential difference
To lower down potential difference

4. Why does a transformer have a core made of iron?

I.  Iron is a conductor of electricity
II.  Iron has a high melting point.
III. Iron is ferromagnetic material
IV.  Iron is electromagnetically soft

I and IV only
II and III only
III and IV only
I, III and IV only

5. Which of the following statement is NOT TRUE about an ideal transformer?
It convert an ac current to dc current
The output power in equal to the input power
Its working principle is based on electromagnetic induction
The output energy is equal to the input energy

6. Which of the following is not the source energy lost in a transformer
Eddy current
Resistance of the coil
Self magnetisation
Flux leakage

7. Which of the following is used to reduce eddy current in a transformer?
Using a soft-iron core
Using a laminating core
Using thick copper wires as the coil
Wind the secondary coil tightly over the primary coils.

8. Which of the following is used to reduce flux leakage in a transformer?
Using a soft-iron core
Using thick copper wires as the coil
Using a laminating core
Wind the secondary coil tightly over the primary coils.

9. A transformer manufacturer found that one of the sources of energy lost in and transformer is magnetisation and reversal of magnetisation of the iron core. Which of the following method can be used to overcome this problem?
Wind the secondary coil tightly over the primary coils.
Using thick copper wires as the coil
Using a soft-iron core
Using a laminating core

10. The frequency of the alternating current in the secondary coil is always __________ the frequency of the current in theprimary coil.
higher than
lower than
equal to