C&G 2357 Unit 309 Mock Exam

This is a C&G 2357 Unit 309 mock exam. In order to simulate the exam conditions we recommend using a stopwatch set to 60 minutes. During that time you need to answer all 30 questions. Remember this is a closed book exam.

You will find the correct answers on the last page. Good luck!

1. What is the unit of measure used for 'work done'?
a) Watt
b) Newton
c) Coulomb
d) Joule

2. What is the SI unit of measure for energy?
a) Newton
b) Coulomb
c) Watt
d) Joule

3. What is the SI unit of measure for power?
a) Watt
b) Newton
c) Kg
d) Joule

4. A mass equal to 45kg is moved a distance of 40m in 25 seconds. Calculate the power?
a) 45000W
b) 720W
c) 706.32W
d) 17658W

5. What is the SI Unit for frequency?
a) Revolutions per second
b) Period
c) Cycles per second
d) Hertz

6. If a motor's input is 75 Watts and its output is 50 Watts, what is the motor's efficiency:
a) 33.3 %.
b) 50 %.
c) 150 %.
d) 66.6 %.

7. Which of the following devices does not use the magnetic effect of electric current?
a) Coil
b) Transformer
c) Battery
d) Relay

8. Which one of the following has the lowest resistivity?
a) Iron
b) Steel
c) Copper
d) Aluminium

9. What cooling medium is normally associated with large transformers?
a) Air
b) Water
c) Ethylene
d) Oil

10. Which one of the following supplies is NOT suitable for a SELV system:
a) an engine-driven generator
b) a double-wound transformer with an earthed secondary winding
c) a lead-acid battery
d) a BS 3535 safety transformer

11. A series circuit consists of three resistors with values of 100 ohm, 250ohm and 350ohm. The total resistance is:
a) 550 ohm
b)300 ohm
c) 70 ohm
d) 700 ohm

12. The meter used in an electrical installation for recording the energy used is called…
a) a wattmeter
b) an ammeter
c) a kilowatt hour meter
d) a power meter

13. Electronic cables are often connected using:
a) terminal blocks
b) grub screws
c) copper connectors
d) IDC connectors

14. When current flow is increased through a conductor, the effect this will have is to
a) increase temperature which will increase resistance
b) increase temperature which will decrease resistance
c) decrease temperature which will increase resistance
d) decrease

15. In a circuit that has a total resistance of 100 and a circuit current of 5 A, the total power dissipated is
a) 500 W
b) 2.5 kW
c) 5.0 kW
d) 50 kW