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# Tag Archives: Glass

## Refraction – Disappearing letters

A rectangular block of glass is placed on a printed page lying on a horizontal table. what is the minimum value of u of glass so that the letters on page are not visible from any of the vertical faces of the block. ## Problem from Ray Optics

A diverging beam of light from a point source S having divergence angle alpha falls symetricaally on a glass slab as shown in fig.The angles of incidence of the two extreme rays are equal.If the thickness of the glass slab is t and the refractive index is n,then the divergence angle of the emergent beam is, a)0
b)alpha
c)sin inverse 1/n
d)2 sin inverse 1/n ## Light Amplification

If you passed directional light from a device such as a laser through the back of a 2 way mirror at a 45 degree angle and then directed that beam to 3 highly reflective mirrors at 45 degree angles in series so that the beam was directed back to the exact point it emerges from the two way mirror and creates an infinate loop what would happen? Would the beam change color since the particles would be out of sync because of the time delay?  Would the light and heat of the beam amplify itself if the reflective surfaces were reflecting more than 50% of all the light emitted and more than 50% of the original sources light were transferred through the 2 way mirror?  I included a drawing to simpilify the questions. ## Heat! Heat! Heat! Thermal vibration of a segment of protein alpha helix. The amplitude of the vibrations increases with temperature. (Photo credit: Wikipedia)

A glass ball at -10 degrees C is placed in 500 ml of water at 20 degrees C. The final temp is 15 degrees C.
A. How much heat is lost by the water
B. what is the heat capacity of the water
C. How much heat is gained by the glass ball
D. What is the heat capacity of the glass ball
E. what is the ratio of the heat capacities of the water and the glass ball
F. What is the ratio of the temp changes of the water and glass ball
G. How are the answers to e and f related ### Hits so far @ AskPhysics

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