For sea water with σ = 5 mho/m and ε_r = 80, what is the distance for which ratio signal can be transmitted with 90% attenuation at 25 kHz?

Condition of good conductor:
σ/ϵω >> 1
Equation is given by:
The constant ratio = σ/ϵω
= 44913.6
σ/ϵω >> 1.
hence sea water is a acting as a good conductor Since attenuation is 90%, so transmission is 10%
So,
e^(-αx) = 0.1

Attenuation constant = √(σμϵ/2)
= 0.702
-αx = ln(0.1)
x = 3.27 m

Determine the ohmic value of the current limiting reactor per phase external to a 30 MVA, 11 kV, 50 Hz, three phase synchronous generator which can limit the current on short circuit of 5 times the full load current. The reactance of the synchronous generator is 0.05 pu.

The ratio of full load current to short circuit current = 1/5
Xsc = j/(1/5)
External reactance required = j*((1/5) - 0.05))
= j*0.15 pu
Full load current = (30*1000)/(√3*11)
= 1574.6 A
Per unit reactance = j*0.15 = (I*Xr)/V
j*0.15 = (1574.6*Xb)/((11/√3)*1000))
= 0.60 ohm

Which of the following is the layer of a computer system between the hardware and the user program?

નીચેના રુઢિપ્રયોગોને અર્થ સાથે સાંકળી જોડી બનાવો.
1. કાન કરડવા - 1. બાતમી મળી જવી.
2. કાન ફૂંકવા - 2. વાત પર ધ્યાન ન આપવું.
૩. કાને વાત પહોચવી - ૩. કાન

Choose the best option from the given alternatives which can be substituted for the given word/sentence

A disease prevailing in a locality

Recently, India signed first ever term contract to import crude oil with which country?