Out of microwaves, ultraviolet rays and infra-red rays, which radiations will be most effective for emission of electrons from metallic surface?

Explanation

To determine which type of radiation (microwaves, ultraviolet rays, or infrared rays) is most effective for the emission of electrons from a metallic surface, we can follow these steps:

### Step 1: Understand the Photoelectric Effect
The emission of electrons from a metallic surface when exposed to light is known as the photoelectric effect. For this effect to occur, the energy of the incoming photons must be greater than the work function of the metal.

### Step 2: Compare the Frequencies of the Radiations
We need to compare the frequencies of microwaves, ultraviolet rays, and infrared rays. The frequency (ν) of electromagnetic radiation is inversely related to its wavelength (λ) and can be expressed as:
\[ c = ν \cdot λ \]
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