4-3。What is the working principle for LED？（ ）
A: convert electric to light
B: convert light to electric
C: convert electric to heat
A: convert electric to light
B: convert light to electric
C: convert electric to heat
举一反三
- The ______cell can convert the energy of sunlight into electric energy.
- The production process of thermal power plant is to convert () of fuel into electric energy. A: chemical energy B: heat energy C: mechanical energy D: kinetic energy
- Why is insulation required in new houses A: To limit discussion on heating bills. B: To prevent heat loss. C: To determine the temperature in homes. D: To convert homes to electric heat.
- We all know that it is Edison who ____________the electric light bulb.
- 中国大学MOOC: The electric lamps went out so she had to candles to light the room.