The intensity is defined as the ratio between the power emitted by the source and the area through which the power is calculated:

(1)
where
P is the power
A is the area
In our problem, the intensity is

. At a distance of r=6.0 m from the source, the area intercepted by the radiation (which propagates in all directions) is equal to the area of a sphere of radius r, so:

And so if we re-arrange (1) we find the power emitted by the source:
t=5s
it was correct on my do-now
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Answer:
heya answer option b
Explanation:
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Answer:
Explanation:
4μC will attract -9μC towards the centre and -5μC will repel it away from the centre. Both these forces are opposite to each other.
Force due to 4μC on -9μC towards the centre
= k x Q₁ Q₂/R² = 9 X 10⁹ X 4 X 10⁻⁶ X 9 X 10⁻⁶ / (1.2)² = 225 X 10⁻³ N/C
Force due to -5μC on -9μC away from the centre
= 9 x 10⁹ x 5 x 10⁻⁶x 9 x 10⁻⁶/( 0.8)² = 632.8 x 10⁻³ .N/C
Ner field =407.8 N/C.