Which of the following statements are correct?

(A) According to wave theory, energy carried by a wave depends on the amplitude of the wave, not on the speed of wave propagation
(B) For a given frequency, intensity of light in the photon picture is determined by the number of photons crossing a unit area
(C) At a large distance from the source, a small portion of the spherical wave can be approximated by a plane wave
(D) the reflected and refracted light both have different frequencies than the incident frequency

Choose the correct answer from the options given below:

(A) and (C) only

The correct answer is Option (2) → (A) and (C) only

(A) Correct — In wave theory, energy carried depends on amplitude, not speed.

(B) Incorrect — Intensity depends on both photon number and energy per photon ($hf$), not only number of photons.

(C) Correct — At large distance, a small part of a spherical wave can be treated as plane wave.

(D) Incorrect — Frequency of light remains unchanged on reflection and refraction.

Correct statements: (A), (C)