Physics , Science-Technology Test 1
Which radioactive pollutant has recently drawn the attention of the public, due to its occurrence in the building material?
  • Radon
  • Radium
  • Plutonium
  • Thorium
Explanation: Radon is a radioactive gas that occurs naturally from the decay of uranium, and it has raised public concern due to its presence in building materials and as an indoor air pollutant. It is a leading cause of lung cancer after smoking.
Permanent hardness of water can be removed by adding
  • Potassium permanganate
  • Bleaching powder
  • Washing soda
  • Chlorine
Explanation: Washing soda (sodium carbonate, Na2CO3) can be used to remove permanent hardness of water by precipitating calcium and magnesium ions as their respective carbonates. This process softens the water.
The mixed oxide fuel is used for which of the following?
  • Cryogenic Engines
  • Nuclear reactors
  • Aeroplanes
  • PSLV rockets
Explanation: Mixed oxide (MOX) fuel is a type of nuclear fuel consisting of a blend of uranium and plutonium oxides. It is primarily used in nuclear reactors as a way to recycle plutonium from spent nuclear fuel and reduce the amount of radioactive waste.
Bar is the unit of
  • Atmospheric pressure
  • Current
  • Heat
  • Temperature
Explanation: Bar is a unit of pressure, commonly used to measure atmospheric pressure. One bar is approximately equal to the atmospheric pressure at sea level, which is 100,000 pascals.
What are soaps?
  • Mixture of glycerol and alcohols
  • Sodium or potassium salts of heavier fatty acids
  • Esters of heavy fatty acids
  • Salts of silicates
Explanation: Soaps are typically formed by the reaction of sodium or potassium hydroxide with fatty acids. This process, known as saponification, results in the formation of soap molecules that have hydrophilic (water-attracting) and hydrophobic (water-repelling) properties.
In radar system, the transmitting antenna is of
  • rotating type in vertical plane
  • rotating type in azimuth
  • rotating type in azimuth or vertical plane of both
  • fixed type
Explanation: In radar systems, the transmitting antenna typically rotates in the azimuth (horizontal plane) to scan a wide area. This allows the radar to detect objects in various directions by emitting radio waves and receiving their reflections.
The inert gas which is substituted for nitrogen in the air, used by deep sea drivers for breathing, is
  • Krypton
    • Explanation: Helium is used as a substitute for nitrogen in breathing mixtures for deep-sea divers. This is because helium is less soluble in the bloodstream and reduces the risk of nitrogen narcosis, a condition that can affect divers at great depths.