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Light, Vision & Optics

Optics is the branch of physics that deals with light and vision. It is primarily the generation, propagation and detection of electromagnetic radiation having wavelengths greater than x-rays and shorter than microwaves. Most optical phenomena can be accounted for using the classical electromagnetic description of light. However, often times these descriptions are too difficult to apply in practice. Practical optics is usually done using simplified models.

Visual perception is the ability to interpret information and surroundings from visible light reaching the eye. The perception which results is known as eyesight or vision. The physiological components involved in vision are referred to as the visual system. There are many focuses of research on visual systems in the fields of psychology, cognitive science, neuroscience and molecular biology.

The visual system in humans allows people to assimilate information from the environment. The act on seeing starts when the lens of the eye focuses an image of its surroundings onto a light-sensitive membrane in the back of the eye. This is called the retina. The retina converts patterns of light into neuronal signals. These signals are processed by different parts of the brain in a hierarchical fashion from the retina to the lateral geniculate nucleus, to the primary and secondary visual cortex of the brain. Signals can also travel directly from the retina to the Superior colliculus. 

Categories within Light, Vision & Optics


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The property possessed by an object of producing different sensations on the eye.


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Polarisation is a property of waves that can oscillate with more than one orientation.

Quantum Properties

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Light displays properties similar to those on the electromagnetic spectrum.

Magnitude and Acceleration and Tension

Two blocks, of weights 3.6 N and 7.2 N, are connected by a mass-less string and slide down a 30 degree inclined plane. The coefficient of kinetic friction between the lighter block and the plane is 0.10; that between the heavier block and the plane is 0.20. Assuming that the lighter block leads, find a) the magnitude of the acce

Questions on basic mechanics

1) Two spherical bodies have masses of 60 and 80 kg, respectively. Determine the force of gravity acting between them if the distance from center to center of the bodies is 500 mm. A) 5.34(10**-7) N B) 0.890(10**-6) N C) 0.890(10**-6) kN D) 1.123(10**6) N 2) How many barrels of oil are contained in 100 kL of oil? One barr

Tension and Moments

A 20.0 kg floodlight in a park is supported at the end of a horizontal beam of mass 20.0 kg and length L that is hinged to a pole (beam and pole are perpendicular). A cable at an angle of 30.0 degrees with the beam helps to support the light. a) Find the tension in the cable. b) Find the horizontal and vertical forces exert

Determining light beams and displacement

A light beam composed of red and blue light is incident upon a rectangular glass plate. The light emerges into the air from point P as two separate beams a. that are parallel, with the red beam displaced below the blue beam. b. that are not parallel, with the blue beam displaced below the red beam. c. that are not parallel

Angular resolution

The angular resolution of a 30 meter diameter radio telescope observing a radio signal of 21 centimeters would be X arcseconds,while the angular resolution of the fully dilated human eye,with diameter of about 5 mm, gathering light at an average of 6x10^(-7) meters in wavelength would be Y?

Gauge pressure, membrane in closed container

Two parts of a closed container are separated by a membrane which only allows the passage of water. Initially each container holds 5 liters of deionized water. To one side is added 22 grams of chlorine and to the other side is added 15 grams of potassium. Each side has a pressure gauge. Which side will record the highest pressur

Calculation of angle of tilt and tension in a string.

A body of mass 10 kg is suspended by a light inextensible string from the roof of a train. Calculate the tension in the string and its inclination to the vertical when the train A. moves with a fixed velocity of 36 km/h. B. accelerates at 2 ms-2, C. decelerates at 6 ms-2

Solving the problem when none or very little water is flowing through your tap.

You live in the ground floor of a high rise apartment block. The over head water tanks which supply water to all the apartments are situated on the rooftop. When water flow through the taps in your apartment is low, you go to inspect the water level in the tank on the rooftop. You check the water level in the tank and do the n