Q. 9

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Found in: Page 790

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# A lightbulb and a lightbulb are placed in the circuit shown in FIGURE . Both bulbs are glowing.a. Which bulb is brighter? Or are they equally bright? b. Calculate the power dissipated by each bulb.

(a) bulb is brighter than bulb.

(b) and

See the step by step solution

## Part (a) step 1: Given information

We have given that the lightbulb and a lightbulb are placed in the circuit shown in FIGURE . Both bulbs are glowing.

We need to find that which bulb is brighter or they equally bright.

## Part (a) step 2: Simplify

When the current flows through a resistor, the energy is dissipated, the rate of the dissipated energy is the power. The power is given as

The formula shows the largest dissipated power if we have several resistors. Solve equation (2) for which is our target to be in the form

The bulbs have power and when the voltage is across each one. So, the resistance for each resistor is given as

and

The dissipated energy increases as the resistance increases. As bulb has the largest resistance, so it is brighter that bulb.

## Part (b) step 1: Given information

We have given that lightbulb and a lightbulb are placed in the circuit shown in FIGURE . Both bulbs are glowing.

We need to calculate the power dissipated by each bulb.

## Part (b) step 2: Simplify

Calculating the current through the circuit by applying the loop rule by

Now, putting the values for , and into equation (3) to get

From Ohm's law , we can get an alternative formula of the dissipated power in the form

Putting the values of and for each bulb