Tag: science & technology

Nokia was founded in Finland in 1865 as a paper mill and later became a telecommunications giant. Finland, not England, Auckland (which is in New Zealand), or Germany, is Nokia's country of origin. The company is synonymous with Finnish innovation in mobile technology.

The Bhagavad Gita consists of 18 chapters, presented as a dialogue between Arjuna and Krishna on the battlefield of Kurukshetra. Each chapter addresses different philosophical concepts like duty, devotion, knowledge, and liberation. The 700 verses are distributed across these 18 chapters, making it a concise yet profound philosophical text.

Samsung Electronics is headquartered in Seoul, South Korea, and is the largest technology company in the country. It was founded in 1969 and has grown to become one of the world's largest electronics manufacturers. North Korea is a separate country with minimal industrial capacity, while South Africa and South America are geographical regions, not countries where Samsung originated.

Motorola was founded in the United States in 1928 by Paul and Joseph Galvin. The company was headquartered in Schaumburg, Illinois for decades before being split and sold to Google and Lenovo. It played a pioneering role in developing mobile phones and telecommunications equipment.

LG Electronics is a South Korean multinational electronics company headquartered in Seoul. It is part of LG Corporation, one of South Korea's largest chaebols (family-controlled conglomerates). LG was originally founded as GoldStar in 1958 and merged with Lucky Chemical to form Lucky-GoldStar, later abbreviated to LG.

All electromagnetic waves (X-rays, gamma rays, infrared, ultraviolet, and visible light) travel at the same speed in a vacuum - the speed of light (c ≈ 3×10^8 m/s). They are not all affected by magnetic fields, not all damaging to health, and they have very different wavelengths.

To solve this question, the user needs to know the basic principles of thermodynamics and the concept of heat transfer through radiation. When an object is heated, it emits thermal radiation in the form of electromagnetic waves. This radiation carries energy away from the object, causing it to cool down.

Now, let's go through each option and explain why it is right or wrong:

A. Electrons: This option is incorrect because the emission of electrons is not a form of heat transfer. Electrons are negatively charged particles that are involved in electrical conduction and chemical reactions, but they do not play a role in thermal radiation.

B. Radio waves: This option is incorrect because radio waves are a type of electromagnetic radiation, but they have a much lower frequency and longer wavelength than the type of radiation emitted by a hot object. Radio waves are typically used for communication and broadcasting, but they are not involved in heat transfer.

C. Visible light: This option is incorrect because visible light is also a type of electromagnetic radiation, but it has a much higher frequency and shorter wavelength than the type of radiation emitted by a hot object. Visible light is responsible for the colors we see, but it is not involved in thermal radiation.

D. Infra-red radiation: This option is correct. Infra-red radiation is a type of electromagnetic radiation that has a frequency lower than visible light but higher than radio waves. It is the type of radiation that is emitted by a hot object as it cools down. Infra-red radiation is responsible for the heat we feel when we stand near a hot object, such as a fire or a stove.

Therefore, the correct answer is: D. Infra-red radiation.

Lead is the best material for storing gamma radioactive substances because it has high density and atomic number, making it an excellent shield against gamma radiation. Graphite, aluminium, and glass offer minimal protection against gamma rays.

Using the formula Energy = Voltage × Charge, we can calculate Charge = Energy / Voltage = 10J / 2V = 5 Coulombs. The relationship E = VQ is fundamental in electrical circuits.