Optics, Physics

A spider is hanging by means of its own silk thread directly above a transparent fixed sphere of r = 20cm .... the refractive index of material of sphere is root(2).... and height of the spider is 2r = 40cm .... an insect initially sitting at the bottom directly below the spider starts crawling along vertical circular path with constant speed pi/4 cm/s.. for how long will the insct be invisible to the spider. Assume that it crawls once around the circle .

Solution) Spider is able to see only half of the sphere which is topmost hemispherical surface. when insct enters in bottom hemispherical surface it becomes invisible for the spider. a/c question insct is travelling vertical circular path it travels pi/4cm in 1sec.then it will travel 2pi r dist i.e. 40picm in 160sec. hence it will travel pi r i.e20pi (half circle) in 80s.

Posted Date: 3/11/2013 1:50:28 AM | Location : United States







Related Discussions:- Optics, Assignment Help, Ask Question on Optics, Get Answer, Expert's Help, Optics Discussions

Write discussion on Optics
Your posts are moderated
Related Questions

Why do magnetic field lines contract longitudinally and exert a lateral pressure?

A thin convex lens of focal length 0.1m and a thin concave lens of focal length 0.1m are placed co-axially in contact. What is the total power of the combination?

What makes a flashlight suddenly become dim or bright when you shake it?

what is plasma and explan in simple word

Can multiple illuminators change colors simultaneously? Yes. Usually the standard disc rotating motors are of the synchronous form, very reliable, and geared to the most suffi

Q. What are the wave fronts? Answer:- (Physics) A wave front is an fantasy surface joining all points in space that are reached at the same instant by a wave propagating th

9.8-g lead bullet with a muzzle velocity of 3.90 x 10 2 m/s is stopped by a wooden block. What is the change in temperature of the bullet if one-fourth of its original kinetic

The refractive index of glass is 1.54. Determine the polarizing angle when light goes from glass to air medium?

Researchers found that a ________ is more important and is the key to losing weight rather than a popular one. A. Fad diet B. Counting calories diet C. Low-carb diet D. Stic