1. Motion, forces and energy

1.1 Physical quantities and measurement techniques

1.2 Motion

1.3 Mass and weight

1.4 Density

1.5.1 Effects of forces

1.5.2 Turning effect of forces

1.5.3 Centre of gravity

1.6 Momentum

1.7.1 Energy

1.7.2 Work

1.7.3 Energy resources

1.7.4 Power

1.8 Pressure

2. Thermal physics

2.1.1 States of matter

2.1.2 Particle model

2.1.3 Gases and the absolute scale of temperature

2.2.1 Thermal expansion of solids, liquids and gases

2.2.2 Specific heat capacity

2.2.3 Melting, boiling and evaporation

2.3.1 Conduction

2.3.2 Convection

2.3.3 Radiation

2.3.4 Consequences of thermal energy transfer

3. Waves

3.1 General properties of waves

3.2.1 Reflection of light

3.2.2 Refraction of light

3.2.3 Thin lenses

3.2.4 Dispersion of light

3.3 Electromagnetic spectrum

3.4 Sound

4. Electricity and magnetism

4.1 Simple phenomena of magnetism

4.2.1 Electric charge

4.2.2 Electric current

4.2.3 Electromotive force and potential difference

4.2.4 Resistance

4.2.5 Electrical energy and electrical power

4.3.1 Circuit diagrams and circuit components

4.3.2 Series and parallel circuits

4.3.3 Action and use of circuit components

4.4 Electrical safety

4.5.1 Electromagnetic induction

4.5.2 The a.c. generator

4.5.3 Magnetic effect of a current

4.5.4 Force on a current-carrying conductor

4.5.5 The d.c. motor

4.5.6 The transformer

5. Nuclear physics

5.1.1 The atom

5.1.2 The nucleus

5.2.1 Detection of radioactivity

5.2.2 The three types of nuclear emission

5.2.3 Radioactive decay

5.2.4 Half-life

5.2.5 Safety precautions

6. Space physics

6.1.1 The Earth

6.1.2 The Solar System

6.2.1 The Sun as a star

6.2.2 Stars

6.2.3 The Universe

IGCSE Physics 4.5.6 The transformer Question Bank

[Maximum number: 1]

The diagram shows a transformer.

What is the output voltage?

$0.35 \mathrm{~V}$

$2.9 \mathrm{~V}$

4600 V

105000 V

[Maximum number: 1]

A transformer has 400 turns on the primary coil connected to the 240 V mains supply.
There are two secondary coils to serve different parts of a television. Secondary coil 1 has 2500 turns and secondary coil 2 has 20 turns.

Which row is correct?

p.d. across secondary coil 1/V

p.d. across secondary coil 2/V

3.2

1500

4200

[Maximum number: 1]

A step-down transformer is 100% efficient. It has an input voltage of 240 V a.c. and an output voltage of 60 V a.c.

The current in the primary coil is 0.50 A.
What is the current in the secondary coil?

$0.13 \mathrm{~A}$

$0.50 \mathrm{~A}$

$2.0 \mathrm{~A}$

$8.0 \mathrm{~A}$

(a)

A student makes a transformer that uses an alternating current (a.c.) supply with an electromotive force (e.m.f.) of 12.0 V to induce an output potential difference (p.d.) of 2.0 V .

The student is provided with two lengths of insulated wire and the U-shaped piece of iron shown in Fig. 7.1.

Fig. 7.1

[ 7 ]

(i)

Complete and label Fig. 7.1 to show the transformer connected to the supply and the output from the transformer.

[ 3 ]

(ii)

Explain the function of the piece of iron in the transformer.

[ 2 ]

(iii)

The output of the transformer is connected to a lamp. The current in the lamp is 100 mA. The transformer is 100% efficient.

Calculate the input current to the transformer.
current =

[ 2 ]

[Maximum number: 1]

Which types of electric current are in the primary coil and the secondary coil of a step-up transformer?

primary

coil

secondary

coil

a.c.

d.c.

a.c.

d.c.

[Maximum number: 1]

A transformer is 100\% efficient.
Which pair of equations are both valid for the transformer?

$I_{\mathrm{p}} V_{\mathrm{p}}=I_{\mathrm{s}} V_{\mathrm{s}} \quad \frac{V_{\mathrm{p}}}{N_{\mathrm{p}}}=\frac{V_{\mathrm{s}}}{N_{\mathrm{s}}}$

$\frac{V_{p}}{I_{p}}=\frac{V_{s}}{I_{s}} \quad N_{p} V_{p}=N_{s} V_{s}$

$\frac{V_{\mathrm{p}}}{I_{\mathrm{p}}}=\frac{V_{\mathrm{s}}}{I_{\mathrm{s}}} \quad \frac{V_{\mathrm{p}}}{N_{\mathrm{p}}}=\frac{V_{\mathrm{s}}}{N_{\mathrm{s}}}$

$I_{p} V_{p}=I_{s} V_{s} \quad N_{p} V_{p}=N_{s} V_{s}$

[Maximum number: 1]

A 24 V power supply and a 100% efficient transformer are used to light a $6.0 \mathrm{~V}, 12 \mathrm{~W}$ lamp.
What is the current in the power supply?

$0.50 \mathrm{~A}$

$2.0 \mathrm{~A}$

$3.0 \mathrm{~A}$

$8.0 \mathrm{~A}$

[Maximum number: 1]

A transformer has 5500 turns on the primary coil and 500 turns on the secondary coil.
The output of the secondary coil is 110 V a.c. and is connected to a heater. The transformer is 100\% efficient.

The heater produces a power of 132 W .
What is the current in the primary coil?

$0.11 \mathrm{~A}$

$0.12 \mathrm{~A}$

11 A

$12 \mathrm{~A}$

[Maximum number: 1]

Which statement about a transformer is correct?

There is an alternating current in the iron core from the primary coil to the secondary coil.

An alternating current in the iron core induces an alternating current in the secondary coil.

An alternating current in the primary coil induces a direct current in the secondary coil.

An alternating current in the primary coil induces an alternating voltage across the secondary coil.

[Maximum number: 1]

A 100% efficient step-down transformer has primary voltage $V_{\mathrm{p}}$ and primary current $I_{\mathrm{p}}$ . Which row compares the secondary voltage with $V_{\mathrm{p}}$ and the secondary current with $I_{\mathrm{p}}$ ?

secondary voltage

secondary current

greater than $V_{\mathrm{p}}$

greater than $I_{\mathrm{p}}$

greater than $V_{\mathrm{p}}$

less than $I_{\mathrm{p}}$

less than $V_{\mathrm{p}}$

greater than $I_{\mathrm{p}}$

less than $V_{\mathrm{p}}$

less than $I_{\mathrm{p}}$

0 selected

Question 25

Question 30

Question 30

Question 7

Question 7(a)

Question 7(a)(i)

Question 7(a)(ii)

Question 7(a)(iii)

Question 31

Question 32

Question 32

Question 32

Question 32

Question 32