Which one of the following cannot emit radiation and why ? Excited nucleus excited electron.

Explanation

To solve the question of which one cannot emit radiation between an excited nucleus and an excited electron, we can follow these steps:

### Step 1: Understand the concept of excited states
An excited state refers to a condition where a particle, such as an electron or a nucleus, has absorbed energy and moved to a higher energy level.

### Step 2: Analyze the excited electron
When an electron is excited, it can transition from a lower energy level to a higher energy level. For example, in a hydrogen atom, an electron can jump from the ground state (n=1) to an excited state (n=2). When the electron returns to a lower energy level, it emits energy in the form of radiation. However, the energy emitted is typically in the range of electron volts (eV), which corresponds to infrared, visible, or ultraviolet radiation.

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