Question 1

An operatic soprano sings a note at 1200 Hz. If the speed of sound in air is $$v = 343\ \mathrm{m/s}$$, what is the wavelength of the sound wave emitted by the soprano?

Accepted Answer

$$0.286\ \mathrm{m}$$

Question 2

A soprano's shriek is measured at the back row of seats, 21.0 m from the stage. If the sound intensity at that location is $$1.00 	imes 10$$^{-6}$$\ \mathrm{W/m^2$}$$, what is the intensity level in decibels (dB)?

Accepted Answer

$$60.0\ \mathrm{dB}$$

Question 3

A spider hangs from a 0.400-m long silk string, which vibrates at its fundamental frequency of 100 Hz. What is the speed of the wave on the string?

Accepted Answer

$$40\ \mathrm{m/s}$$

Question 4

A dermatologist uses a magnifying glass with a focal length of 15.0 cm to examine a mole. If the object (the mole) is placed 10.0 cm from the lens, what is the image distance?

Accepted Answer

$$+30.0\ \mathrm{cm}$$

Question 5

Is the image produced by the magnifying glass in the previous question virtual or real?

Accepted Answer

Virtual

Question 6

A 5.00-cm thick piece of Lucite (index of refraction $$n = 1.50) $$floats in water ($$n = 1.33). A $$laser beam strikes the Lucite at $$60.0^\circ to $$the surface. What is the angle of refraction inside the Lucite?

Accepted Answer

$$36.0^\circ$$

Question 7

Which of the following best describes the phenomenon when two pulses on a string meet and the resulting displacement is the sum of the individual displacements?

Accepted Answer

Superposition principle

Question 8

Parallel rays of light incident on a concave mirror converge at a single point. What is this point called?

Accepted Answer

Focal point

Question 9

A laser beam is directed at the surface of a calm pond. Which of the following organisms would be struck by the laser light, according to the law of reflection?

Accepted Answer

The snail and the fish

Question 10

A current loop is placed between two bar magnets. Which of the following best describes the behavior of the loop?

Accepted Answer

Counterclockwise rotation

Question 11

A dermatologist examines a mole with a 5.00 mm diameter using a magnifying glass with a magnification of 3.0. What is the size of the image?

Accepted Answer

$$15.0\ \mathrm{mm}$$

Question 12

A soprano runs toward the audience while singing a 1200 Hz note. If she runs at 2.00 m/s and the speed of sound is 343 m/s, what frequency does a stationary audience member hear?

Accepted Answer

$$1207\ \mathrm{Hz}$$

Question 13

Which equation correctly relates the speed of a wave on a string to its tension and mass per unit length?

Accepted Answer

$$v = \sqrt{\frac{T}{\mu}}$$

Question 14

If the index of refraction of Lucite is 1.50 and that of water is 1.33, which of the following is true about the speed of light in Lucite compared to water?

Accepted Answer

Light travels slower in Lucite than in water

Question 15

A dermatologist holds a lens such that the distance between the lens and the image is 30.0 cm, and the object is 10.0 cm from the lens. What is the focal length of the lens?

Accepted Answer

$$15.0\ \mathrm{cm}$$

Physics Exam IV Study Guidance: Waves, Sound, Optics, and Magnetism

Study Guide - Practice Questions

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