Question

Consider two identical electric bulbs of power P and resistance R. You connect them to a battery of voltage V. The first time you connect them in series with each other, and the second time in parallel. How will the illumination of the connection in parallel compare with the connection in series?
a. 1/2 of the illumination of connection in series

b. 2X as much illumination as connection in series

c. 1/4 of the illumination of connection in series

d. The same illumination as connection in series

e. 4X greater illumination as connection in series

Answer 1

Answer:

E

Explanation:

When the two identical electric bulbs of power P and resistance are connected in series;

P = IV = V ( V/R) = V² / R

and V = IR

for series connection, the effective resistance Rf = R + R = 2R

and current in the circuit I₁ = V / 2R

for the parallel connection ,

$\frac{1}{Rf}$ = $\frac{1}{R}$ +

Rf = R / 2

I₂, in the circuit = 2 V / R

comparing the current,

I₂ ÷ I₁ = 2 V / R ÷ V / 2R = 4 : 1

The illumination is 4 times as greater in connection in series

Answer 2

Answer:

The answer is 2X as much illumination as connection in series

Explanation:

We are given from the question that the two bulbs are identical in power and resistance.

Firstly we know that In a series connection the Voltage across the circuit elements are different whereas In a parallel connection, the same value of voltage passes through all the circuit elements.

Power is expressed as ;

P = V^2/ R

An increase in voltage leads to an increase in power likewise if the voltage is reduced the power also reduces.

The two bulbs are said to be having the same resistances , so the voltage across them in a series connection will be halved

V =1/2V1 + 1/2 V2; making the illumination across them to be low.

Therefore in parallel the illumination will be twice as much the illumination when connected in series.