The primary reason why the colour red is used for danger signals is that red light is scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Therefore blue which has the least wavelength of all the visible radiations is scattered the most and red which has the highest wavelength of all the colours we can see is scattered the least. So red light is able to travel the longest distance through fog, rain, and the alike. Also, red is a colour we inherently perceive as one that is associated with danger.

Correct Option: B

The primary reason why the colour red is used for danger signals is that red light is scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a colour. Therefore blue which has the least wavelength of all the visible radiations is scattered the most and red which has the highest wavelength of all the colours we can see is scattered the least. So red light is able to travel the longest distance through fog, rain, and the alike. Also, red is a colour we inherently perceive as one that is associated with danger.

Nose bleeds can occur at high altitudes. The bleeding may be caused by the change in air pressure associated with the change in altitude or the cold dry air common at high altitudes. No matter the cause, the symptoms and treatment of a high altitude bloody nose are the same. A nose bleed is defined as the discharge of blood from the nostrils. Stress and anxiety raises the blood pressure, complicating the nose bleed. At high elevations, there’s less oxygen in the air for us to breathe in. When we travel from a low elevation to a high one, our body needs time to adjust to the lower levels of oxygen reaching your bloodstream. Eventually, our respiration and heart activity increase and we produce more red blood cells to transport the oxygen to where it needs to go.

Correct Option: C

Nose bleeds can occur at high altitudes. The bleeding may be caused by the change in air pressure associated with the change in altitude or the cold dry air common at high altitudes. No matter the cause, the symptoms and treatment of a high altitude bloody nose are the same. A nose bleed is defined as the discharge of blood from the nostrils. Stress and anxiety raises the blood pressure, complicating the nose bleed. At high elevations, there’s less oxygen in the air for us to breathe in. When we travel from a low elevation to a high one, our body needs time to adjust to the lower levels of oxygen reaching your bloodstream. Eventually, our respiration and heart activity increase and we produce more red blood cells to transport the oxygen to where it needs to go.

An atomic clock is a clock device that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

Correct Option: C

An atomic clock is a clock device that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities. The equation is how to reconcile with this result of special relativity with Newton’s second law, F=ma. It would be seen that any constant force, no matter how small, applied for a considerably very long time, should continuously accelerate any mass ‘m’ at a rate a=f/m until the speed was arbitrarily very large. Einstein, concluded that energy has inertia i.e. the more energy a body possess, the more inertia that body will display. Since, inertia is a property of matter, which is associated with mass. Thus from Einstein’s argument mass is simply a property attributed to the total energy of the body and only the total energy is required, to know the total mass of the body.

Correct Option: D

Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities. The equation is how to reconcile with this result of special relativity with Newton’s second law, F=ma. It would be seen that any constant force, no matter how small, applied for a considerably very long time, should continuously accelerate any mass ‘m’ at a rate a=f/m until the speed was arbitrarily very large. Einstein, concluded that energy has inertia i.e. the more energy a body possess, the more inertia that body will display. Since, inertia is a property of matter, which is associated with mass. Thus from Einstein’s argument mass is simply a property attributed to the total energy of the body and only the total energy is required, to know the total mass of the body.

Cryogenics is the study of how to get to low temperatures and of how materials behave when they get there. Besides the familiar temperature scales of Fahrenheit and Celsius (Centigrade), cryogenicists use other temperature scales, the Kelvin and Rankine temperature scales. One of the more modern processes being used to treat metals (as well as other materials) is cryogenic tempering. While the science of heat treatment is well known and widely understood, the principles of cryogenic tempering remain a mystery to most people in industry.

Correct Option: B

Cryogenics is the study of how to get to low temperatures and of how materials behave when they get there. Besides the familiar temperature scales of Fahrenheit and Celsius (Centigrade), cryogenicists use other temperature scales, the Kelvin and Rankine temperature scales. One of the more modern processes being used to treat metals (as well as other materials) is cryogenic tempering. While the science of heat treatment is well known and widely understood, the principles of cryogenic tempering remain a mystery to most people in industry.