Which of the following parts of the sunlight makes the solar cooker hot? (1) Ultraviolet (2) Red light (3) Infrared (4) Cosmic rays Answer: (3) Glass transmits visible light but blocks infrared thermal radiation from escaping. This amplifies the heat-trapping effect. A solar cooker, or solar oven, is a device that uses the energy of direct … Read more
If the velocity-time graph of a particle is represented by y = mt + c, then the particle is moving with (1) constant speed (2) constant velocity (3) constant acceleration (4) varying acceleration Answer: (3) In this case the given equation shows that that the velocity is linear with time and therefore the particle is moving … Read more
Which of the following occurred first? (1) Albert Einstein propounded the General Theory of Relativity (2) Max Planck unveiled the Quantum Theory (3) Guglielmo Marconi sent out the first wireless signals (4) Wright Brother’s successfully flew an aircraft Answer: (3) Guglielmo Marconi sent out the first wireless signals. In the early summer of 1895 and despite … Read more
A passenger standing in a bus is thrown outward when the bus takes a sudden turn. This happens due to (1) Outward pull on him (2) Inertia of motion (3) Change in momentum (4) Change in acceleration Answer: (2) This is the inertia of direction. It is the ability of the body to be in a … Read more
When pressure is increased the melting point of ice (1) increases (2) does not change (3) decreases (4) depends on the impurities in the ice Answer: (3) In this case, if we increase the pressure on the ice the ice-water system wants to try to lower it again. It can do that by making itself fit … Read more
Longitudinal waves cannot travel through (1) Vacuum (2) Solid (3) Liquid (4) Gas Answer: (1) Longitudinal wave cannot travel through a vacuum because such wave requires a medium such as solid-liquid or air to travel through. They cannot travel through a vacuum or in space. Longitudinal waves, also known as “l-waves”, are waves that have the … Read more
Electrostatic precipitator is used to control the pollution of (1) air (2) water (3) noise (4) thermal Answer: (1) An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge. An electrostatic precipitator (ESP) or electrostatic … Read more
Tungsten is used for the manufacture of the filament of an electric bulb, because (1) It is a good conductor (2) It is economical (3) It is malleable (4) It has a very high melting point Answer: (4) Tungsten is used because it has the highest melting point of all the metallic elements. It melts at … Read more
What is the wavelength of the visible spectrum? (1) 1300 A°–3000 A° (2) 3900 A° – 7600 A° (3) 7800 A° – 8000 A° (4) 8500 A° – 9800 A° Answer: (2) The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in … Read more
Who measured the velocity of light first? (1) Galileo (2) Newton (3) Romer (4) Einstein Answer: (3) Galileo is often credited with being the first scientist to try to determine the speed of light. Galileo’s experiment was carried out by the Accademia del Cimento of Florence, Italy, in 1667, with the lanterns separated by about one … Read more