In a filament-type bulb, a lot of electric energy is wasted in the form of :

Options

A. magnetism
B. sound
C. light
D. heat

Answer

To solve the question "In a filament-type bulb, a lot of electric energy is wasted in the form of:", we will analyze the options provided and determine which one correctly identifies the form of wasted energy.

### Step-by-Step Solution:

1. **Understanding the Function of a Filament Bulb**:
- A filament bulb is designed to produce light when electric current passes through it. The filament, usually made of tungsten, heats up and emits light.

2. **Analyzing the Options**:
- **Option 1: Magnetism** - Filament bulbs do not produce magnetism as a byproduct of their operation. Thus, this option can be eliminated.
- **Option 2: Sound** - Typically, filament bulbs do not produce sound when they are turned on. This option can also be eliminated.
- **Option 3: Light** - The primary purpose of a filament bulb is to produce light. Therefore, light cannot be considered as wasted energy.
- **Option 4: Heat** - When electric current passes through the tungsten filament, a significant amount of energy is converted into heat rather than light. This heat is often considered wasted energy because it does not contribute to the primary function of the bulb.

3. **Conclusion**:
- After analyzing all the options, we can conclude that the correct answer is **heat**. In a filament-type bulb, a lot of electric energy is wasted in the form of heat.

### Final Answer:
**Heat**

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