Q.Survey of Doping in Sports — talk to at least 15 sportspersons or athletes from your school, or a nearby school (you could also talk to people who regularly go to a gym for a workout). Fill up the following questionnaire (rate No / Don't know / Maybe / Probably / Yes): Do you think doping is necessary to achieve the best results? Does anyone you know use performance-enhancing drugs? Are you aware of the substances you cannot use in competitions? Do you think your performance would improve by banned substances? Have you ever tried any banned substances to improve performance? Are you aware of the side effects of doping? Is the NADA doping test available for the tournaments/competitions you participate in? According to you, who recommends performance enhancing drugs to players? Have you felt a pressure to use banned substances? Based on the survey above, and your own ideas, make a PPT on Doping and Sports.

Doping: The Intuition

Imagine you have a pure block of silicon. Silicon is a semiconductor — it's not a good conductor like copper, but it's not an insulator either. In its pure form, every silicon atom is neatly bonded to four neighbours, sharing electrons perfectly. There are no free electrons to carry current easily.

Now, what if you could deliberately add a tiny amount of an impurity — just a few atoms per million — to change how easily electricity flows through that block? That's exactly what doping does.

Think of it like adding a pinch of salt to plain water. The water itself doesn't change much, but suddenly it conducts electricity far better because the salt breaks into charged particles. Doping is the semiconductor equivalent: you add a controlled impurity to dramatically alter the electrical behaviour of the material.

The Precise Definition

The key words are intentional and controlled. Unwanted impurities ruin a semiconductor; doping is the deliberate, precise addition of specific atoms to achieve a desired property.

How It Works: Two Flavours

1. n-type doping (negative type)

You add an atom that has five valence electrons (like phosphorus, arsenic, or antimony) to a silicon crystal that has four. Four of those electrons bond with neighbouring silicon atoms, but the fifth electron has nowhere to go — it becomes a free electron that can move easily through the crystal. The impurity is called a donor because it donates an electron.

2. p-type doping (positive type)

You add an atom that has three valence electrons (like boron, aluminium, or gallium). It tries to bond with four silicon neighbours but can only form three bonds. The missing bond creates a hole — a place where an electron is absent. This hole behaves like a positive charge carrier. The impurity is called an acceptor because it accepts an electron (leaving a hole behind). …