Alexandra Nastasa

Numerade Educator
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Biography

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Education

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Educator Statistics

Numerade tutor for 6 years
15 Students Helped

Topics Covered

Cellular Respiration and Fermentation: Understanding the Basics
Understanding Electromagnetic Waves: A Comprehensive Guide
Understanding Reflection and Refraction of Light: A Comprehensive Guide

Alexandra's Textbook Answer Videos

05:45
Physics

Kim says that she was less than 10 ft away from the president when she took a picture of him with her $50-\mathrm{mm}$ focal length camera lens. The picture shows the upper half of the president's body (or $3.0 \mathrm{ft}$ of his total height). On the negative of the film, this part of his body is $18 \mathrm{mm}$ high. How close was Kim to the president when she took the picture?

Chapter 24: Optical Instruments
Alexandra Nastasa
04:30
Physics

Esperanza uses a 35 -mm camera with a standard lens of focal length $50.0 \mathrm{mm}$ to take a photo of her son Carlos, who is $1.2 \mathrm{m}$ tall and standing $3.0 \mathrm{m}$ away. (a) What must be the distance between the lens and the film to get a properly focused picture? (b) What is the magnification of the image? (c) What is the height of the image of Carlos on the film?

Chapter 24: Optical Instruments
Alexandra Nastasa
05:03
Physics

Jim plans to take a picture of McGraw Tower with a 35 mm camera that has a 50.0 -mm focal length lens. A roll of 35 -mm film is 35 mm wide; each frame is 24 mm by
$36 \mathrm{mm} .$ The tower has a height of $52 \mathrm{m}$ and Jim wants a detailed close-up picture. How close to the tower should Jim be to capture the largest possible image of the entire tower on his film?
(FIGURE CANNOT COPY)

Chapter 24: Optical Instruments
Alexandra Nastasa
03:13
Physics

If a slide of width $36 \mathrm{mm}$ (see the figure with Problem 16) is to be projected onto a screen of $1.50 \mathrm{m}$ width located $12.0 \mathrm{m}$ from the projector, what focal length lens is required to fill the width of the screen?

Chapter 24: Optical Instruments
Alexandra Nastasa
05:24
Physics

A converging lens with focal length $3.00 \mathrm{cm}$ is placed $4.00 \mathrm{cm}$ to the right of an object. A diverging lens with focal length $-5.00 \mathrm{cm}$ is placed $17.0 \mathrm{cm}$ to the right of the converging lens. (a) At what location(s), if any, can you place a screen in order to display an image? (b) Repeat part (a) for the case where the lenses are separated by $10.0 \mathrm{cm}.$

Chapter 24: Optical Instruments
Alexandra Nastasa
01:59
Physics

Unless the problem states otherwise, assume that the distance from the comea-lens system to the retina is $2.0 \mathrm{cm}$ and the normal near point is $25 \mathrm{cm}.$
If the distance from the lens system (cornea + lens) to the retina is $2.00 \mathrm{cm},$ show that the focal length of the lens system must vary between $1.85 \mathrm{cm}$ and $2.00 \mathrm{cm}$ to see objects from $25.0 \mathrm{cm}$ to infinity.

Chapter 24: Optical Instruments
Alexandra Nastasa
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