Fill in the following blanks with suitable words :
When current is switched 'on' in a room heater, its element becomes ________.

Answer

To fill in the blank in the statement "When current is switched 'on' in a room heater, its element becomes ________," we can follow these steps:

1. **Understand the Function of a Room Heater**: A room heater is designed to generate heat. It does this by passing electric current through a heating element.

2. **Identify the Heating Effect of Electric Current**: When electric current flows through a conductor (in this case, the heating element), it generates heat due to the resistance of the material. This is known as the heating effect of electric current.

3. **Consider the Physical Change of the Heating Element**: As the current flows through the heating element, the element heats up. If the current is sufficiently strong, the heating element can become very hot, often to the point of glowing.

4. **Choose the Appropriate Term**: Based on the heating effect and the physical change of the heating element, the most suitable word to fill in the blank is "red hot." This term indicates that the heating element not only becomes hot but reaches a temperature where it emits a red glow.

Thus, the completed statement is: "When current is switched 'on' in a room heater, its element becomes **red hot**."

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