Continuous spectrum is produced by

Options

A. incandesent electric bulb
B. sum
C. hydrogen molecules
D. sodium vapor lamp

Explanation

To solve the question "Continuous spectrum is produced by," we need to analyze the characteristics of continuous spectra and the conditions under which they are produced.

### Step-by-Step Solution:

1. **Understanding Continuous Spectrum**:
- A continuous spectrum is a range of wavelengths or frequencies of electromagnetic radiation that contains all the colors or energies without any gaps. This is typically represented graphically with energy on one axis and wavelength on the other.

2. **Source of Continuous Spectrum**:
- Continuous spectra are produced when matter is heated to high temperatures, causing atoms to vibrate and emit radiation across a continuous range of wavelengths. This is often seen in incandescent sources.

3. **Bulk State of Matter**:
- Continuous spectra are associated with the bulk state of matter, where a large number of atoms or molecules are present. In this state, the thermal vibrations of the atoms lead to the emission of radiation at all frequencies.

4. **Comparison with Discrete Spectra**:
- In contrast, discrete spectra are produced by individual atoms or molecules transitioning between specific energy levels. This is not the case for continuous spectra, which do not have specific energy transitions.

5. **Examples of Continuous Spectrum**:
- Common examples of sources that produce continuous spectra include:
- The Sun, which emits a broad range of wavelengths due to its high temperature.
- Incandescent light bulbs, where the filament heats up and emits light across a continuous range.

6. **Conclusion**:
- Therefore, continuous spectra are produced by thermal vibrations in the bulk state of matter, where atoms vibrate at all frequencies, leading to the emission of radiation across a continuous range.

### Final Answer:
Continuous spectrum is produced by **bulk state of matter** (e.g., incandescent light bulbs, the Sun).

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