Tag: science & technology

'h.s.' is the medical abbreviation for 'hora somni,' Latin for 'at bedtime.' This is used in prescriptions to indicate medication should be taken before going to sleep, not during or at other times.

Iron is ferromagnetic - it's strongly attracted to magnets and can be magnetized itself. Tin, copper, and magnesium are not magnetic (they are paramagnetic or diamagnetic with very weak responses). This is a fundamental property used in distinguishing materials and building electromagnets.

The ampere (A) is the SI unit of electric current - one of the seven base SI units. Watt measures power, joule measures energy, and volt measures electric potential difference. Current is the flow of electric charge, and its unit is named after André-Marie Ampère.

Kinetic energy is the energy possessed by an object due to its motion - literally 'energy in motion.' The faster an object moves, the more kinetic energy it has. Potential energy (C) is stored energy based on position, Brownian motion (A) is random particle movement, and 'vectorial' (D) is not a standard energy type.

Gravitational potential energy near Earth's surface is PE = mgh, where m is mass, g is gravitational acceleration (9.8 m/s²), and h is height. Option A (0.5 mv²) is kinetic energy. Option B (mc²) is Einstein's mass-energy equivalence. Option D (m²v) is not a standard physics formula.

Alpha radiation consists of helium nuclei (2 protons + 2 neutrons) emitted during radioactive decay. When a nucleus emits an alpha particle, it loses 2 protons and 2 neutrons. Beta particles are electrons, gamma rays are electromagnetic waves, and 'delta' is not a type of radiation.

Beta decay involves a neutron converting to a proton (emitting an electron and antineutrino). This increases the atomic number by 1 (more protons) but mass number stays nearly the same (proton+neutron count unchanged). Option A describes neither decay type. Option C describes alpha decay. Option D is incorrect.

Fraunhofer lines are dark absorption lines in the solar spectrum, caused by elements in the Sun's outer atmosphere absorbing specific wavelengths. They were first systematically studied by Joseph von Fraunhofer in 1814. The other named scientists contributed to other areas of physics.

Planck's constant (h ≈ 6.626 × 10⁻³⁴ J·s) is a fundamental constant in quantum mechanics, relating the energy of a photon to its frequency (E = hf). The symbols g (gravity), c (speed of light), and p (momentum) represent other physical quantities.

The Heisenberg Uncertainty Principle, formulated by Werner Heisenberg in 1927, states that certain pairs of physical properties (like position and momentum) cannot both be precisely known simultaneously. Δx·Δp ≥ ℏ/2. Einstein, Rutherford, and Schrödinger made other major contributions to quantum physics.