Electricity and Circuits - SS1 Physics Past Questions and Answers - page 4
A household appliance has a power rating of 800W and is used for 3 hours per day. How much energy does it consume in a week?
To calculate the energy, we multiply the daily energy consumption by the number of days in a week.
Daily energy consumption = 800W × 3h = 2400Wh
Weekly energy consumption = 2400Wh × 7 days = 16,800Wh or 16.8 kWh.
A refrigerator has a power rating of 150W. If it operates continuously for 24 hours, how much energy does it consume?
To calculate the energy, we can use the formula E = P × t, where E is the energy, P is the power, and t is the time.
Plugging in the given values, we get E = 150W × 24h = 3,600Wh or 3.6 kWh.
What is the purpose of using insulation on electrical wires?
To reduce resistance in the circuit
To increase the current flow
To prevent electric shocks
To enhance the brightness of the lights
What should you do if you need to remove a plug from an electrical outlet?
Pull the plug out by the cord
Tug on the cord forcefully
Turn off the circuit breaker before removing the plug
Use a metal object to pry the plug out
What is the purpose of a circuit breaker or a fuse in an electrical circuit?
To increase the voltage of the circuit
To regulate the current flow
To provide a path for current to flow
To protect against overcurrent and prevent electrical fires
What should you do if you notice frayed or damaged electrical cords?
Use them as they are but handle them with caution
Tape the damaged area with electrical tape
Replace the damaged cords with new ones
Ignore the damage and continue using the cords
What is the purpose of grounding in an electrical system?
To increase the resistance in the circuit
To decrease the voltage in the circuit
To prevent electrical appliances from working
To provide a safe path for excess electrical current to flow to the ground
Why is it important to wear insulated gloves and safety glasses when working with electrical circuits? Discuss the potential hazards and how these safety precautions mitigate them.
It is important to wear insulated gloves and safety glasses when working with electrical circuits to protect oneself from potential hazards. When working with electricity, there is a risk of electrical shock or arc flash, which can cause serious injuries.
Insulated gloves provide a barrier between the hands and the electrical components, preventing direct contact with live wires and reducing the risk of electrical shock. Safety glasses, on the other hand, protect the eyes from any sparks, debris, or chemicals that may be released during electrical work, preventing eye injuries.
Explain the importance of proper grounding in electrical circuits.
Proper grounding is essential in electrical circuits to ensure safety and protect against electrical faults. Grounding provides a safe path for excess electrical current to flow into the ground, preventing electrical shocks and fires. Without proper grounding, electrical faults such as short circuits or equipment malfunctions can cause electrical current to flow through unintended paths, such as the human body. This can result in severe injuries or even fatalities.