A parallel circuit contains four identical lamps. The current through the energy source is 4 A. The total resistance of the circ
uit is 10 Ω. What is the voltage across the energy source and across each lamp?
a)2.5 V; 40 V
b)40 V; 40 V
c)2.5 V; 2.5 V
d)40 V; 2.5 V
a)2.5 V; 40 V
b)40 V; 40 V
c)2.5 V; 2.5 V
d)40 V; 2.5 V
1 answer:
Answer:
b. 40V , 40V
Explanation:
Connections are as per the figure.
As total current through source is 4A , current through each lamp is 1A.
As total resistance of the circuit is 10Ω ,resistance of each bulb is 40Ω because in case of a parallel circuit in which identical objects are connected , where R is the resistance of each bulb and n is the number of bulbs.
As per Ohm's law , voltage of the source =IR = 4×10 =40V.
We can see from the figure that if the voltage across the source is 40V , the voltage across each bulb is also 40V.
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The intensity depending on the power is defined as
Where
P = Power
r = Radius
Replacing the values that we have,
The definition of intensity tells us that,
Where,
Magnetic field
Permeability constant
c = Speed velocity
Then replacing with our values we have,
Re-arrange to find the magnetic Field B_0
Therefore the amplitude of the magnetic field of this light is