Electric Circuits

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Which of the following is the correct unit of measurement for resistance in an electric circuit?

Amperes

Volts

Watts

Ohms (correct)

What is the purpose of a voltmeter in an electric circuit?

To measure the current flowing in the circuit

To measure the resistance of the load

To measure the voltage across the load (correct)

To measure the emf of the battery

Which component is always connected in series to the load in an electric circuit when measuring current?

Ohmmeter

Ammeter (correct)

Multimeter

Voltmeter

What is the function of a multimeter in an electric circuit?

To measure the voltage, current, and resistance Signup and view all the answers

Which of the following is a factor that determines the severity of injury from an electric shock?

The length of time the current flows through the body Signup and view all the answers

What is the maximum current that can be fatal in an electric shock?

50 mA Signup and view all the answers

What should you do if someone is shocked or burned by electricity and is still in contact with the live circuit?

Switch off the electrical supply and call for help Signup and view all the answers

What is the recommended action if you cannot find the electrical supply source when someone is shocked or burned by electricity?

Do not touch the victim Signup and view all the answers

Which of the following is NOT one of the learning objectives for the unit on Electrical Safety?

Explain the two types of electric shock: Direct contact and Indirect contact Signup and view all the answers

Which of the following is NOT a type of electric shock?

Grounded contact Signup and view all the answers

What is the purpose of a multimeter in electrical work?

To test for electrical continuity Signup and view all the answers

Which of the following is NOT one of the sub-units in the section on Electrical Principles and Circuits?

Electrical Test Instruments Signup and view all the answers

Which formula can be used to calculate the total resistance of a series circuit with two resistors?

$RT = \frac{R1 \cdot R2}{R1 + R2}$ Signup and view all the answers

In a series circuit, the total resistance is higher than the highest individual resistance.

True Signup and view all the answers

In a parallel circuit, the total resistance is lower than the lowest individual resistance.

True Signup and view all the answers

What is the total resistance of a parallel circuit with two resistors, where $R1 = 80 , \Omega$ and $R2 = 160 , \Omega$?

$34.29 , \Omega$ Signup and view all the answers

According to Ohm's law, the current flowing through a conductor is directly proportional to the potential difference applied across its ends, provided the temperature remains constant. Which equation represents Ohm's law?

$V = I \times R$ Signup and view all the answers

What is the formula to calculate the voltage in a circuit, given the current and resistance?

$V = I \times R$ Signup and view all the answers

In a simple electric circuit, a load of resistance 500 Ω is connected to a supply of 230 V. What is the current drawn?

0.46 A Signup and view all the answers

In a series circuit comprising two resistors, what is the formula to calculate the total resistance?

$RT = R1 + R2$ Signup and view all the answers

Which formula can be used to determine the power in an electric circuit comprising one electrical load?

$P = V imes I$ Signup and view all the answers

What is the power dissipated in a 10 Ω resistor connected to a voltage of 220 V?

4.84 kW Signup and view all the answers

What is the rated current and resistance of a 60 W, 230 V bulb?

Current: 0.26 A, Resistance: 884.62 Ω Signup and view all the answers

What is the energy consumption of an electrical load with a power of 50 W, in kilowatt-hours?

0.05 kWh Signup and view all the answers

Which equation represents the conversion between kilowatt-hours and joules?

1 kWh = 3.6 × 10^7 J Signup and view all the answers

What is the electrical energy used by a 1,000 W heater turned on for 10 hours?

360,000 J Signup and view all the answers

What is the energy consumed by a 2 kW refrigerator turned on for 24 hours per day in one month (30 days)?

1440 kWh Signup and view all the answers

What is the cost of using a refrigerator at $0.25 per unit if it consumes 1440 kWh?

$360 Signup and view all the answers

What is the total energy consumed by a 1,000 W heater for 30 days if it is turned on for an average of 10 hours per day?

300 kWh Signup and view all the answers

What are the three main components of an energy bill in Singapore?

electricity, gas, water Signup and view all the answers