Electrical Energy and Power

Question 1

What is electrical energy, and how is it calculated?

Answer 1

Electrical energy is the energy produced or consumed by the movement of electric charges in a circuit. It is calculated using the formula: 𝐸 = 𝑃 × 𝑡
where
𝐸 is electrical energy in joules (J),
𝑃 is power in watts (W), and
𝑡 is time in seconds (s).

Question 2

What is electrical power, and how is it related to energy?

Answer 2

Electrical power is the rate at which electrical energy is consumed or produced in a circuit. It is given by the formula:
𝑃 = 𝐸 / 𝑡
where 𝑃 is power in watts (W),
𝐸 is energy in joules (J), and
𝑡 is time in seconds (s).

Question 3

What is the commercial unit of electrical energy, and how is it converted to joules?

Answer 3

The commercial unit of electrical energy is the kilowatt-hour (kWh). It is the energy consumed when 1 kilowatt of power is used for 1 hour.
Formula: 1kWh = 3.6 × 10⁶J

Question 4

What is the heating effect of electric current, and how is it calculated?

Answer 4

The heating effect of electric current is the production of heat when an electric current flows through a conductor due to its resistance.
Formula: 𝐻 = 𝐼² 𝑅𝑡
where 𝐻 is the heat produced in joules (J),
𝐼 is the current in amperes (A),
𝑅 is the resistance in ohms (Ω), and 𝑡 is time in seconds (s).

Question 5

How is the fuse rating in an electrical circuit determined?

Answer 5

The fuse rating is the current at which the fuse will blow, protecting the circuit from excessive current. It is determined using the power and voltage of the circuit:
Formula: 𝐼𝑓 = 𝑃 / 𝑉
where 𝐼𝑓 is the fuse rating in amperes (A), 𝑃 is the power in watts (W), and 𝑉 is the voltage in volts (V).