The story of Electricity：練習問題

Many electrical appliances have a standby mode. Why is it recommended to turn off the power at the wall socket rather than just using the remote control to put the device on standby?

In a circuit with two bulbs, \(B1\) and \(B2\), and one battery, a student notices that when bulb \(B1\) is unscrewed from its holder, bulb \(B2\) immediately goes out as well. What can be concluded about the circuit's design?

Why are portable electronic toys usually designed to run on batteries rather than being connected directly to the high-voltage mains electricity (wall sockets)?

When comparing two different light bulbs, Bulb X uses \(60\text{W}\) of power and Bulb Y (an LED) uses only \(9\text{W}\) to produce the same amount of brightness. If both are used for 10 hours a day, which statement about resource conservation is correct?

When investigating the conversion of energy in household appliances, which of the following best describes the energy transformation that occurs in an electric doorbell while it is ringing?

In a simple circuit with one battery and one light bulb, explain what will happen if you place a second battery facing in the opposite direction to the first one.

Explain how a short circuit is different from a normal closed circuit, and describe the primary safety hazard it creates.

Imagine you are explaining the principles of electricity to a younger student. Provide detailed answers to the following parts:

a) What are the three essential parts of a simple circuit required to make a bulb light up? Explain why the electricity stops flowing when a switch is moved to the 'off' (open) position.

b) When we use electricity, we are often converting it into other useful forms. State the primary energy conversion that takes place in (i) an electric fan and (ii) an electric iron.

c) In terms of safety, explain what a 'short circuit' is and why it is considered a dangerous situation in a home environment.

d) We are encouraged to 'make good use of resources' by saving electricity. Identify two specific actions you can take to save energy and explain why using less electricity helps protect the environment.