The peak electric field produced by the radiation coming from the 8 W bulb at a distance of 10 m is . The efficiency of the bulb is 10% and it is a point source. The value of x is ______.

CONCEPT:

• The intensity is defined as the ratio of the power to the area and it is written as;

           Intensity, I =  ⇒ I = 

          Here we have " I " as the intensity, P is the Power and A is the area.

• The intensity with electric field is written as;

           I = 

           Here we have c as the velocity, ϵ_o as permittivity of the free space, and E_o is the electric field.

CALCULATION:

Given: Power, P = 8 W

distance, r = 10 m 

As we know that the intensity is  I = 

and also it is written as, I = 

Here the area is written as, A = 

Now, by putting all the given values we have;

⇒ I =  = 

⇒  = 

Here we have  = 

⇒  = 

⇒  = 

⇒ 

Therefore the value of x is 2