### What multiple of distance between the centre of the earth and that of the moon is the distance between the centre of the earth and the geostationary satelite which always stays above the fixed location on the equator ? take the cycle of revolution of the moomn around the earth to be 27 days ?

According to Kepler’s third law of planetary motion
T2=R3 ( For geo stationary satellite)-------1
T’2=R’3( For Moon)----------------------------2
Dividing eq(2) by eq(1), we get
T’2 / T2=R’3/ R3
Since T’=27 T
Then we can write as
27 T2 /T2= R’3/ R3
Or
R’3=27 R3
Or

R’=3 R
or
R= 1/3 R'
so the distance between the centre of the earth and the geostationary satellite which always stays above the fixed location on the equator is 1/3 times distance between the centre of the earth and that of the moon .

### COMMON COLLECTOR CONFIGURATION OF A TRANSISTOR

COMMON COLLECTOR CONNECTION

In  this  configuration  the  input  is  applied  between the  base  and  the  collector and  the  output  is  taken  from  the  collector  and  the  emitter.  Here  the  collector  is common to both the input and the output circuits as shown in Fig.

Common Collector Transistor Circuit

In  common  collector  configuration  the  input  current  is  the  base current  IB  and  the output current is the emitter current IE. The ratio of change in emitter current to the  change in the base current is called current amplification factor.

It is represented by

COMMON COLLECTOR CIRCUIT

A test  circuit  for determining the  static characteristic  of an NPN transistor is shown in Fig. In this circuit the collector is common to both the input and the output circuits.   To   measure   the   base   and   the   emitter   currents,   milli   ammeters   are connected in series with the base and the emitter circuits. Voltmeters are connected   across the input an…