Em Spectrum - Visible Light

1. How many colours are there in the spectrum?

4

8

7

The spectrum refers to the range of colors that are visible to the human eye when white light is passed through a prism. This range consists of seven colors: red, orange, yellow, green, blue, indigo, and violet. Therefore, the correct answer is 7.

Explanation

The spectrum refers to the range of colors that are visible to the human eye when white light is passed through a prism. This range consists of seven colors: red, orange, yellow, green, blue, indigo, and violet. Therefore, the correct answer is 7.

2. Red has the shortest wavelength

True

False

The statement "Red has the shortest wavelength" is false. In the visible light spectrum, red light has the longest wavelength, while violet light has the shortest wavelength. The order of the visible light spectrum from longest to shortest wavelength is: red, orange, yellow, green, blue, indigo, and violet.

Explanation

The statement "Red has the shortest wavelength" is false. In the visible light spectrum, red light has the longest wavelength, while violet light has the shortest wavelength. The order of the visible light spectrum from longest to shortest wavelength is: red, orange, yellow, green, blue, indigo, and violet.

3. Visible light rays cannot be seen by the naked eye.

True

False

Visible light rays can be seen by the naked eye. Visible light refers to the range of electromagnetic radiation that is visible to humans. It includes the colors of the rainbow, such as red, orange, yellow, green, blue, indigo, and violet. These colors can be seen by the naked eye when light enters the eye and is detected by the photoreceptor cells in the retina. Therefore, the statement that visible light rays cannot be seen by the naked eye is false.

Explanation

Visible light rays can be seen by the naked eye. Visible light refers to the range of electromagnetic radiation that is visible to humans. It includes the colors of the rainbow, such as red, orange, yellow, green, blue, indigo, and violet. These colors can be seen by the naked eye when light enters the eye and is detected by the photoreceptor cells in the retina. Therefore, the statement that visible light rays cannot be seen by the naked eye is false.

4. Violet has the longest wavelength

True

False

The statement "Violet has the longest wavelength" is incorrect. In the visible light spectrum, violet light actually has the shortest wavelength. The colors in the visible light spectrum are arranged in increasing order of wavelength, with red having the longest wavelength and violet having the shortest.

Explanation

The statement "Violet has the longest wavelength" is incorrect. In the visible light spectrum, violet light actually has the shortest wavelength. The colors in the visible light spectrum are arranged in increasing order of wavelength, with red having the longest wavelength and violet having the shortest.

5. When all the waves are seen together, they make black light.

True

False

The statement "When all the waves are seen together, they make black light" is incorrect. When all the waves are seen together, they make white light, not black light. White light is a combination of all visible colors of light, while black light is the absence of light or the complete absence of any color.

Explanation

The statement "When all the waves are seen together, they make black light" is incorrect. When all the waves are seen together, they make white light, not black light. White light is a combination of all visible colors of light, while black light is the absence of light or the complete absence of any color.