Question

studying brightness
study figures b and c. answer the questions.
figure b shows two light - bulbs. both are the same distance from the girl.

1. which bulb glows more brightly?

x y

1. you would make both bulbs seem brighter by moving them the girl.

closer to, farther away from

1. how would you make bulb x seem as bright as bulb y? list two ways.

a)
b)
figure c shows stars. stars x and y seem equally bright. yet, x really gives off more light than y.

1. which star is farther away?

x, y

1. which star is closer?

x, y

Explanation:

Step1: Compare bulb wattages

Higher - wattage bulb is brighter. Bulb Y is 100 watts and bulb X is 50 watts. So bulb Y glows more brightly.

Step2: Understand light - distance relationship

The closer a light source is to an observer, the brighter it appears. So moving the bulbs closer to the girl makes them seem brighter.

Step3: Make bulb X as bright as Y

To make bulb X as bright as bulb Y, we can either increase the wattage of bulb X (make it a higher - wattage bulb) or move bulb X closer to the girl (decrease the distance between bulb X and the girl).

Step4: Analyze star brightness and distance

If two stars seem equally bright but one gives off more light in reality, the one that gives off more light is farther away. So star X is farther away.

Step5: Determine closer star

Since star X is farther away and stars X and Y seem equally bright, star Y is closer.

Answer:

1. Y
2. closer to
3. a) Increase the wattage of bulb X. b) Move bulb X closer to the girl.
4. X
5. Y