Explanation

An Angstrom (Å) measures very small distances, especially wavelengths of light and atomic-scale lengths.

It is equal to 10^-10 meters, or 0.1 nanometers. 

Therefore, among the given options, angstrom is used to measure the length of light waves.

It is also used to measure other microscopic dimensions, such as: 

• The size of atoms and molecules
• The lengths of chemical bonds
• The arrangement of atoms in crystals

Explanation

The Metric System of Measurements uses the mass units: gram (g), kilogram (kg), and tonne (t). 1000 g = 1 kg. 1000 kg = 1 tonne.

Mass was first defined in 1795

Symbol: M

Explanation

Electric flux is given by Φ = E × A, so its SI unit is (N/C) × m² = N·m²/C.

It represents the number of electric field lines passing through a surface.

Explanation

In 1820, Hans Christian Oersted discovered that an electric current produces a magnetic field around it.

This discovery laid the foundation of electromagnetism.

Explanation

An electron gun emits a focused beam of electrons using thermionic emission.

It is commonly used in cathode ray tubes, microscopes, and TVs.

Explanation

A transformer can increase (step-up) or decrease (step-down) the voltage of alternating current (AC).

It's widely used in power transmission to reduce energy loss over long distances.

Explanation

At maximum height, the vertical component of velocity becomes zero, so speed is minimum.

Only the horizontal component of velocity remains constant.

Explanation

Due to inertia of motion, when the bus stops suddenly, passengers tend to keep moving forward.

Without support, this causes them to lose balance and fall.

Explanation

An adiabatic change happens when a gas expands or compresses without heat exchange with surroundings.

The change in temperature occurs due to internal energy variation only.

Explanation

At diastolic pressure, blood moves smoothly in parallel layers without disruption, called laminar flow.

Laminar flow ensures efficient and quiet blood circulation in vessels.