Explanation

Silicon is widely used in semiconductors because:

• It is abundant in nature.
• It has suitable electrical properties.
• It has excellent thermal stability.
• It forms a stable oxide layer (SiO₂) useful in device fabrication.

Note: Germanium was used earlier, and gallium nitride is used for high-power or high-frequency devices, but silicon remains the standard.

Last updated 14-feb-2026

Explanation

• Rear view mirrors in vehicles are convex mirrors.
• They give a wider field of view.
• Images formed are virtual, upright, and smaller.
• This helps drivers see more traffic behind them.
• It is a curved mirror that bulges outward.
• It is commonly used in side mirrors of cars, buses, and motorcycles.

Last verified 26-04-2026

Explanation

• Dispersion is the optical phenomenon where white light is split into its constituent colors, also known as a spectrum.
• This occurs when light passes through a medium with a refractive index that varies with wavelength, such as a prism.

The process of dispersion involves two stages:

1. Refraction (bending of light)
2. Separation of colors (splitting into distinct colors)

The seven distinct colors that make up the visible spectrum, in order, are:

1. Red
2. Orange
3. Yellow
4. Green
5. Blue
6. Indigo
7. Violet

Last verified on 11-11-2026

Explanation

• A convex lens is thicker at the centre than at the edges.
• It converges parallel rays of light to a focal point.

Last verified on 11-11-2026

Explanation

• An electric generator is a device that converts mechanical energy into usable electrical energy.
• This process is based on the principle of electromagnetic induction.
• Discovered in 1831 by British scientist Michael Faraday.

Last verified on 27-04-2026