Correct Option
The correct option is (c).
Explanation
The working of an electric heater is based on the heating effect of electric current (Joule’s Heating). When an electric current passes through a conductor, electrical energy is converted into heat energy. The amount of heat produced is governed by the formula \( H = I^2Rt \), where \( I \) is current, \( R \) is resistance, and \( t \) is time.
Statement-wise Analysis
- Statement 1 is Correct: The heating element is made of a material (alloy) that possesses high electrical resistance and a high melting point (e.g., Nichrome). High resistance ensures that a significant amount of heat is generated when current flows through it, as heat generation is directly proportional to resistance (\( H \propto R \)).
- Statement 2 is Incorrect: The element does not absorb heat from the surroundings; rather, it dissipates heat to the surroundings. It acts as a source of thermal energy by converting electrical potential energy into heat energy.
- Statement 3 is Correct: The wire is typically coiled to increase its effective length within a limited space. Since resistance is directly proportional to length (\( R \propto L \)), increasing the length increases the total resistance, thereby enhancing heat production. Coiling also concentrates the heat in a specific area.
Key Takeaway
Joule's Law of Heating dictates that for a given current, the heat produced is proportional to the resistance of the conductor. Therefore, heating elements utilize materials with high resistivity and are designed with sufficient length (often coiled) to maximize resistance and heat output.