Visible light is the tiny part of the EM spectrum our eyes can see. Its wavelength runs from about 400 nm (violet) to 700 nm (red), and its frequency from about 4 x10^14 Hz to 7 x10^14 Hz. It sits between infrared (longer wavelength, lower frequency) and ultraviolet (shorter wavelength, higher frequency), and it is produced by electron transitions inside atoms. Memory hook: "VIBGYOR = 400 to 700" - Violet is the short end (400 nm), Red is the long end (700 nm).
Visible light (400 nm violet to 700 nm red) is a narrow band wedged between infrared (longer wavelength) and ultraviolet (shorter wavelength). Wavelength falls and frequency rises as you move from red toward violet.
Your doubts, answered
Is the visible range 400-700 nm or 380-780 nm? Which do I write in NEET?
NCERT gives about 400 nm to 700 nm (and in one line 400-750 nm). For NEET, use 400 nm to 700 nm - that is the number the exam expects. The 380-780 nm figure comes from other books; do not use it in NEET unless an option forces it. In frequency this is about 4 x10^14 Hz to 7 x10^14 Hz.
Does red light or violet light have higher frequency?
Violet has the higher frequency. Violet is at the short-wavelength end (about 400 nm) and red is at the long-wavelength end (about 700 nm). Since frequency f = c / wavelength, a shorter wavelength means a higher frequency. So violet (about 7 x10^14 Hz) beats red (about 4 x10^14 Hz).
What lies just before and just after visible light in the spectrum?
Order by increasing frequency: infrared -> visible -> ultraviolet. Infrared sits at the long-wavelength (red) side of visible light and has lower frequency. Ultraviolet sits at the short-wavelength (violet) side and has higher frequency. So the neighbours of visible light are infrared and ultraviolet.
How is visible light produced?
Visible light is produced mainly by electron transitions in atoms - an electron jumps from a higher energy level to a lower one and releases a photon of visible energy. This is the standard NEET match: visible light -> electron transitions in atoms (unlike gamma rays from the nucleus, or microwaves from klystron/magnetron valves).
Why does the eye see only this tiny band and not radio waves or X-rays?
Because the retina is chemically sensitive only to photons in the 400-700 nm energy range. Other EM waves either carry too little energy per photon (radio, microwave, infrared) or too much (UV, X-ray, gamma) to trigger the eye's receptors. So the eye is a very narrow detector on a huge spectrum.
⚠️ The NEET trap ✗ Red light has higher frequency than violet because red 'looks stronger'. ✓ Violet has higher frequency and shorter wavelength; red has lower frequency and longer wavelength. Colour brightness has nothing to do with frequency order. 🧠 Short wavelength = high frequency. Violet (400 nm) is short, so violet is high-frequency. Red (700 nm) is long, so red is low-frequency.
Real NEET questions
2026
Match List I (Electromagnetic wave) with List II (Production): (A) Microwave (B) Visible light (C) Gamma rays (D) Infrared; (I) Electron transitions in atoms (II) Radioactive decay (nuclear transitions) (III) Vibration of atoms and molecules (IV) Klystron or magnetron valve.
A · A-III, B-I, C-II, D-IV
B · A-III, B-IV, C-I, D-II
C · A-IV, B-I, C-II, D-III ✓
D · A-IV, B-III, C-II, D-I
Solution: Match each source. Step 1: Microwaves are made by special vacuum tubes -> klystron or magnetron valve, so A-IV. Step 2: Visible light comes from electron transitions in atoms (an electron drops to a lower level and emits a visible photon), so B-I. Step 3: Gamma rays come from the nucleus, i.e. radioactive decay / nuclear transitions, so C-II. Step 4: Infrared is emitted by vibration of atoms and molecules (heat), so D-III. Combining: A-IV, B-I, C-II, D-III = option (C).
2022
Match List I (Electromagnetic waves) with List II (Wavelength): (a) AM radio waves (b) Microwaves (c) Infrared waves (d) X-rays; (i) 10^-10 m (ii) 10^2 m (iii) 10^-2 m (iv) 10^-4 m.
A · a-iv, b-iii, c-ii, d-i
B · a-iii, b-ii, c-i, d-iv
C · a-iii, b-iv, c-ii, d-i
D · a-ii, b-iii, c-iv, d-i ✓
Solution: Order by wavelength (longest to shortest). Step 1: AM radio waves are longest, about 10^2 m -> a-ii. Step 2: Microwaves are in the centimetre range, about 10^-2 m -> b-iii. Step 3: Infrared is shorter, about 10^-4 m -> c-iv. Step 4: X-rays are shortest here, about 10^-10 m -> d-i. Visible light (about 4-7 x10^-7 m) would sit just below infrared and above X-rays. Answer: a-ii, b-iii, c-iv, d-i = option (D).
Solved Electromagnetic Waves NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
What is the wavelength range of visible light for NEET?
About 400 nm to 700 nm (violet to red). NCERT also states 400-750 nm in one place, but 400-700 nm is the standard NEET value.
What is the frequency range of visible light?
About 4 x10^14 Hz to 7 x10^14 Hz. The 4 x10^14 Hz end is red (long wavelength) and the 7 x10^14 Hz end is violet (short wavelength).
Where does visible light sit in the EM spectrum?
Between infrared and ultraviolet. Infrared is on the low-frequency (long-wavelength) side and ultraviolet is on the high-frequency (short-wavelength) side.
How is visible light produced?
Mainly by electron transitions in atoms - electrons falling from higher to lower energy levels emit visible photons. This is the common NEET match-the-column answer.
Which colour has the longest wavelength and which the shortest?
Red has the longest wavelength (about 700 nm) and violet has the shortest (about 400 nm). Order VIBGYOR runs from short (violet) to long (red).
