Railway RRB / NTPC - MCQ Practice Questions

The speed of light in vacuum is approximately 3 × 10^8 meters per second or 300,000 km/s.

Insulin, produced by the pancreas, regulates blood glucose levels by promoting glucose uptake and storage.

Common salt is sodium chloride (NaCl), composed of sodium and chlorine ions.

Solar energy is a renewable source that can be replenished naturally, while coal, natural gas, and petroleum are non-renewable fossil fuels.

Hydrochloric acid (HCl) is secreted by the stomach lining and helps in the digestion of proteins.

Vitamin D is produced by the body when skin is exposed to ultraviolet rays from the sun.

Oxygen is essential for aerobic respiration in most organisms. It is used in cellular respiration to produce energy (ATP).

The four fundamental states of matter are solid, liquid, gas, and plasma. Energy is not a state of matter; it is a property or capability of matter to do work.

Carbon has an atomic number of 6, meaning it has 6 protons in its nucleus. Its atomic mass is approximately 12.

Coal is a non-renewable fossil fuel that takes millions of years to form. Solar, wind, and hydroelectric are renewable sources.

Using Distance = Speed × Time: Distance = 3 × 10⁸ × 2 = 6 × 10⁸ meters.