4 replies to this topic

[betty]

The ASTRA satellite transmits radio waves (speed = 3 ´ 108 m/s) at a frequency of 12.5 GHz (1 GHz = 1 ´ 109 Hz).

(a) What is the wavelength of the signal?

(b The transmitting dish is 1.6 m in diameter. Find the angle of diffraction.

© What is the radius of the circular patch that receives the signal? The height of the satellite is 3.6 ´ 107 m above the earth. (Ignore the curvature of the Earth)


the solution is :
a) l = c/f = 3 ´ 108 m/s ¸ 12.5 ´ 109 Hz = 0.024 m (= 2.4 cm)



(b sin = l/a = 0.024 m/1.6 m = 0. 015



= sin-1 0.015 = 0.86



© Radius = 3.6 ´ 107 m ´ tan 0.86 = 3.6 ´ 107 m ´ 0.015


= 540 000 m (= 540 km)

[u]

but answer © how does it come like that why >> Radius = the hieght of satalite multiblied by tan 0.86

[Art Montemayor]

Betty:

What does this topic have to do with Analytical Chemistry or Chemical Engineering?

[betty]

it is according to diffraction and intereferenc tests..I is important for me as a process engineer to have an idea about the technologies are use in laporties of industries..

[betty]

no replay!!!!!!!!!!

[Qalander (Chem)]

Dear betty, I can not make any co-relationship between
a) Diffraction Gratting
Interference
with the satellite dish? does this form a source to be used as monochromic light for spectro photometer or other machines.
Please clarify.