All about POWER and ENERGY!
Complete the questions to the finish line. Don't give up and enjoy the game
Question 1
What is the effect of placing a piece of soft iron inside a solenoid carrying a current?
The resistance of the solenoid decreases
The current in the solenoid increases
The magnetic field becomes stronger
Nothing happens
Question 2
A magnetic field is produced by the current in a long straight wire. The strength of the magnetic field increases if
The magnitude of the current increases
The distance from the wire increases
The length of the wire increases
Reverse the direction of current flow through the wire
Question 3
The function of the commutator in a d.c. motor is
to reverse the current in the coil at every half rotation
to enable the coil to be in electrical contact with the carbon brushes
The prevent the wires from entangling
to ensure the current flows in external circuit
Question 4
In Fleming's right-hand rule, the first finger points in the direction of
the magnetic field
the current
the force
the motion
Question 5
An ideal transformer has 400 turns in the primary coil and 580 turns in the secondary coil. When a 240 V supply is supplied to the primary coil, an 8 A current flows through it. What is the current in the secondary coil?
1.8 A
2.6 A
4.3 A
5.5 A
Question 6
Soft iron is used as the core of a transformer because
soft iron has low resistance
soft iron becomes a permanent magnet
soft iron is easily magnetised and demagnetised
soft iron is a better conductor than steel
Question 7
What is the function of the soft iron core of a transformer?
Magnetic flux produced by the primary coil passes through the secondary coil
Current from the primary coil flows into the secondary coil
Reduce the resistance in the circuit
To support the structure of the coil wound on it
Question 8
Which of the following is true for an ideal transformer?
The output voltage equals the input voltage
The output power equals to the input power
The output voltage is higher than the input voltage
The output current is equals to the input current
Question 9
Which of the following will increase the efficiency of a transformer?
Use insulated wires for the coils
Use steel for the core
Wind the primary and secondary coils on the same limb of the core
Use a.c supply for the input
Question 10
Which of the following sources of energy used for generation of electric causes air pollution?
Hydro
Wind
Wave
Coal
Question 11
What is the advantages of transmitting electricity in the form of alternating current?
Power loss in the cables is reduced
A.c is easier to generate
Voltage of a.c can be stepped up or stepped down using transformers
A.c is safer than d.c
Question 12
The main source of energy for electrical power generation in Malaysia is
hydro
natural gas
wind
geothermal
Question 13
The national grid network for electrical power generation consists of
a power station supplying power to all parts of the country
various power stations connected to cables supplying power to all part of the country
many power stations and each station supplies power to a particular part of the country
Question 14
Which of the following is an advantage of the national grid network?
Electrical power can be supplied to all part of the country
Loss of power from cables is reduced
Disruption to electricity supply due to power station breakdown is reduced
Question 15
Electricity is transmitted at a very high voltage in order to
increase the current in the cables
reduce the resistance of the cables
reduce power loss
increase the resistance of the cables