Question

. A light bulb glows because of it’s resistance, and the brightness of the bulbincreases with the electrical power delivered to it from the circuit. In the circuitbelow, the two bulbs are identical. Compared to bulb A, does bulb B glow morebrightly, less brightly or equally bright (when the bulbs are both in the circuit on theleft)?

Answer 1

Complete Question

The complete question is shown in the first uploaded image

Answer:

a

When the both bulb are in the circuit  bulb B glows equally brighter to bulb A

This because the power delivered to the both bulb are equal

b

The bulb A on the right will glow brighter than the bulb A on the left due to the fact that the power supplied to bulb A on the right is higher than that gotten by bulb A on the left.

Explanation:

From the question we are been told that the two bulbs are identical

So their resistance denoted by R is the same

Considering the left circuit  where the two bulbs are connected in series which mean that the same current is passing through them

               $R_A =R_B =R$

                $i_A = i_B =i$

               $R_{eq} = R_1 +R_2 = 2R$

                       $i = \frac{V}{2R}$  

The power that is been deposited on the circuit is evaluated as

                   $P_A = i^2R$

                   $P_A = \frac{V^2}{4R}$

                  $P_B = i^2R$

                   $P_B = \frac{V^2}{4R}$

For the fact that the power deposited on the bulbs are the same they will glow equally

When B is now removed and only A is left

                $R_{eq} = R_A = R$

                   $i = \frac{V}{R}$

                   $P'_A = i^2R$

                    $P'_A = \frac{V^2}{R}$

For the fact that its only bulb A that is on that right circuit the power delivered  to it would be greater compared to the left circuit bulb A