1) Which measurement represents three-dimensional space? a) a. Area  b) b. Density c) c. Volume d) d. Width 2) Which temperature scale is an SI base unit? a) a. Celsius  b) b. Degrees c) c. Fahrenheit d) d. Kelvin 3) What is the SI unit for time? a) a. Day  b) b. Second c) c. Minute d) d. Hour 4) The distance between two sub-stations is 4,564 metres. How would this value be represented in kilometres? a) a. 4564km  b) b. 4.564km c) c. 0.456km d) d. 45.64km 5) Calculate (3 × 4) (7 + 3) a) a. 22  b) b. 122 c) c. 120 d) d. 100 6) What is 133mV in volts? a) a. 0.133V  b) b. 133V c) c. 13.3V d) d. 0.013V 7) What quantity of power is produced if a domestic circuit is supplied with 230V and draws 20A of electrical current? a) a. 23kW  b) b. 0.087W c) c. 4.6kW d) d. 4.6W 8) What type of energy is produced when a dart is thrown onto a board? a) a. Mechanical  b) b. Potential c) c. Real d) d. Kinetic 9) A toolbox weighs 200kg. How much work is needed to lift it to a height of 2m? a) a. 400J  b) b. 100J c) c. 3.9kJ d) d. 4kJ 10) What is potential difference measured in? a) a. Amps  b) b. Ohms c) c. Watts d) d. Volts 11) How is resistance defined? a) a. Provides assistance to current flow  b) b. Provides reduction to current flow c) c. Provides amplification to current flow d) d. Provides opposition to current flow 12) Which multiplication factor represents the prefix Mega? a) a. 10⁻³  b) b. 10 ³ c) c. 10⁻⁶ d) d. 10 ⁶ 13) Which metal is known to be the best conductor of electricity? a) a. Gold  b) b. Aluminium c) c. Silver d) d. Copper 14) An electric current in a circuit may be described as a a) a. flow of atoms  b) b. flow of protons c) c. flow of neutrons d) d. flow of electrons 15) What is the force called which acts towards the centre of the earth? a) a. Work  b) b. Gravity c) c. Mass d) d. Weigh 16) If one of the resistors shown in the image is 3Ω, what is the value of the other? a) a. 7Ω  b) b. 2Ω c) c. 3Ω d) d. 5Ω 17) Which is common in a parallel circuit? a) a. Voltage b) b. Current c) c. Power d) d. Resistance 18) What current will flow in the circuit if all the resistors are rated at 10Ω? a) a. 12A  b) b. 4A c) c. 0.25A d) d. 3600A 19) A luminaire is very dim. What is likely to be the cause? a) a. Excess current drop  b) b. Excess voltage drop c) c. Excess resistance drop d) d. Excess power drop 20) Which is not an effect of passing current through a conductor of electricity? a) a. Thermal  b) b. Magnetism c) c. Chemical d) d. Nuclear 21) Which symbol represents flux density? a) a. B  b) b. ∅ c) c. Weber d) d. Tesla 22) Lines of magnetic field flow from which direction? a) a. North to north  b) b. South to south c) c. North to south d) d. South to north 23) A sine wave has a peak voltage of 100V. What is its RMS value? a) a. 70.7V  b) b. 1414V c) c. 63.7V d) d. 50V 24) Which device is used as an amplifying device or functions as an electronic switch? a) a. Triode  b) b. Thyristor c) c. Transistor d) d. Thermocouple 25) What is the component shown in the image? a) a. Light-emitting diode  b) b. Light-dependent diode c) c. Light-dependent resistor d) d. Light-emitting resistor 26) How is 400V obtained? a) a. By measuring from line to neutral  b) b. By measuring from line to earth c) c. By measuring from line to line d) d. By measuring from neutral to earth 27) What kind of device changes its resistance following a change in temperature?  a) a. Thermocouple  b) b. Transistor c) c. Transformer d) d. Thermistor 28) What distribution voltage is used to supply the light industry? a) a. 132kV  b) b. 11kV c) c. 33kV d) d. 400kV 29) Which device is used to provide electrical separation? a) a. RCBO  b) b. RCD c) c. Circuit breaker d) d. Transformer 30) A transformer has a turns ratio of 1:5. If 100V is supplied to its primary coils, calculate its secondary voltage a) a. 500V  b) b. 20V c) c. 5V d) d. 1,000V 31) What would be the effect of increasing the number of secondary turns on a transformer? a) a. Decreased output voltage  b) b. Increased output voltage c) c. Decreased input voltage d) d. Increased input voltage 32) Which protective device tracks the waveform of the supply? a) a. RCD  b) b. AFDD c) c. RCBO  d) d. SPD 33) An electrical conductor has a resistance of 10Ω. Which value indicates its resistance should its cross-sectional area be doubled? a) a. 20Ω  b) b. 5Ω c) c. 2.5Ω d) d. 40Ω 34) A sine wave has a periodic time of 20ms. Calculate its frequency. a) a. 0.02Hz  b) b. 0.2Hz c) c. 5Hz d) d. 50Hz 35) What current will flow in the circuit if all the resistors are rated at 10Ω? a) a. 12A  b) b. 4A c) c. 0.25A d) d. 3600A 36) What does the first finger represent in the image? a) a. Direction of current  b) b. Direction of voltage c) c. Direction of thrust d) d. Direction of magnetic field 37) Which electromagnetic device can provide multiple outputs when activated by a single input? a) a. Transformer  b) b. Diode c) c. Relay d) d. Thyristor 38) What is the value of the unknown side? a) a. 360.5A  b) b. 22.36A c) c. 223.6A d) d. 10A 39) The resistance of a kettle element is 19.2Ω. What amount of current will flow through the element if it’s supplied with 230V? a) a. 0.0834A  b) b. 11.97A c) c. 6.66A d) d. 4416A 40) What is the total resistance of the network shown in the image? a) a. 300.0Ω  b) b. 20.0kΩ c) c. 66.6kΩ d) d. 66.7Ω

Electrical Science 2

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