Modern Physics and Electronics

Physics

Chapter - 13: Modern Physics and Electronics

👉 All Chapter Contents 👈 

What is radioactivity?

Radioactivity is the emission or transmission of ion in the form of waves or particles through space or material medium by the spontaneous disintegration of atomic nuclei.

What is called Becquerel?

Becquerel is the SI unit of radioactivity, corresponding to one disintegration per second.

What is meant by the half-life of radioactive element?

The time in which half of the nucleus disintegrates (or radiates) is known as the half life is. The half life of a stable nucleus having no radioactivity can be considered to be 'infinity'.

Radioactivity is a nuclear phenomenon - explain.

Radioactivity is a nuclear phenomenon because a nucleus is transformed into another through radioactive emission. Due to radioactivity, radioactive rays emerge and this changes the structure of the nucleus and turn it into a different element. A different nucleus can accept or donate one or two electrons from surrounding to become a charge less atom.

How is ECG different from ETT?

ETT stands for exercise tolerance test while ECG stands for Electro-Cardiogram. ETT is nothing but an ECG since it is done during the time the patient is taking an exercise  with either a treadmill or a stationary bicycle while ECG is done when the patient is in rest.

Why it is suitable to use optical fiber to send electrical signal at long distance?

Infrared rays of long wavelength are used n optical fibers. Because of using infrared rays, the absorption of light in optical fibers is very low and light can be taken hundreds of kilometers through optical fibers. Infrared light propagates through the fiber with much lower attenuation compared to electrical cables. That is why; it is suitable to use optical fiber to send electrical signals at long distances.

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Question Bank

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13.1 Radioactivity

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Secondary Physics