Science final exam

what color of light is produced when red light is added to green light

yellow

Longitudinal wave and transverse wave

A longitudinal wave is a wave that moves parallel to the direction of the disturbance of the particles. A transverse wave is a wave that moves perpendicular to the direction of the disturbance of the particles.

Eye glass some one should wear who can not focus on near by objects

Convex lenses should be prescribed. Convex lenses focus light slightly before it enters the eye so that the lens of the eye can focus the light properly on the retina.

why is it difficult to see though glass that has frost of it

Frost is translucent, so the light traveling through it is scattered as it passes through.

how are gamma rays used

Gamma rays are used to treat some forms of cancer and are used to kill harmful bacteria in foods.

How is a hologram different from a photo graph

Holograms have three-dimensional images that appear in front of or behind the surface of the film. Photographs have two-dimensional images on their surfaces.

Describe how a whale uses the doppler effect

If a fish is moving away from the whale, the echo off the fish that the whale hears will have a lower pitch than the original sound. If the fish is moving toward the whale, the echo off the fish heard by the whale will have a higher pitch than the original sound.

briefly describe what happens in the ear

In the outer ear, sound waves are funneled into the ear canal. In the middle ear, the hammer, anvil, and stirrup increase the size of the vibrations. In the inner ear, these vibrations are changed into electrical signals for the brain to interpret.

explain how the colors of the rainbow create white light

My brother's conclusion is wrong because he is confusing mixing of light (color addition) with mixing of pigments (color subtraction).

Reflection and refraction

Reflection occurs when a wave strikes a barrier and reverses direction. Refraction occurs when a wave enters a different medium and its speed and direction change.

why might a scientist who is working at the north pole need polarizing sunglasses

The North Pole is covered with snow that reflects a great deal of light. The reflected light is polarized and can be eliminated by using sunglasses with polarizing lenses.

How do vibrations cause sound waves

The back-and-forth motions of vibrations of an object cause compressions and rarefactions in the air around it, which is carried outward as sound waves.

A certain sound wave travels thought water with a certain wavelength, frequency, and wave speed. A second wave with twice the frequency of the first wave then travels thought the same water. What is the second wave's wavelength and wave speed compared to those of the first wave

The second wavelength will have half the wavelength of the first wave and the same wave speed. (Wave speed depends on the medium, and not on wavelength or frequency.)

why does a tern see a fish in the wrong place

The tern sees the fish in the wrong place because light refracts as it passes from the water to the air. This creates an optical illusion for the tern

Explain in terms of resonance how opera singers can break glass

The vibrations from the singer's voice cause the glass to vibrate at one of its resonant frequencies. It does not take much to make it vibrate with a large amplitude. But the glass is not very flexible, so it shatters.

Effects of the ear

The worker may be suffering from tinnitus, caused by long exposure to loud sounds. Further hearing loss could be prevented by wearing hearing protection while on the job.

How do some walls absorb sound

This design eliminates echoes because the surfaces of the walls absorb sound waves instead of reflecting them.

what are two uses for radio waves

Two uses for radio waves are the broadcasting of radio signals and the broadcasting of television signals.

what is the relationship between frequency, wave speed, and wavelength

Wave speed is the frequency multiplied by the wavelength. The longer the wavelength, the lower the frequency. The shorter the wavelength, the higher the frequency.

Wavelength and amplitude

Wavelength is the distance between corresponding points on a wave. Amplitude is the maximum distance that the medium is displaced by the wave.

You have lost the paddles for the canoe you rented, and the canoe has drifted to the center of a pond. You need to get it back to the shore, but you do not want to get wet by swimming in the pond. Your friend suggest that you drop rocks behind the canoe to create waves that will push the canoe toward the shore. With this solution work?

Waves carry energy, not matter. So, waves will make the canoe bob up and down in the pond but will not push the canoe closer to the shore.

Using the concept of interference, explain why the sound levels in the music room vary

With constructive interference, the crest of one wave overlaps with the crest of another wave, making a new wave with a higher crest and greater amplitude or loudness. With destructive interference, the crest of one wave overlaps with the trough of another wave, decreasing the amplitude and making the sound softer.

what kind of mirror provided images of large areas and is used for security

a convex mirror

If two sound waves interfere constructively, you will hear___.

a louder sound

you will hear a sonic boom when___.

a shock wave reaches you ear

sound travels fastest though___.

air

which kind of electromagnetic wave travels fastest in a vacumm

all travel the same speed

The wave property that is related to the height of a wave is the___

amplitude

A fisherman in a row boat notices that one wave crest passes his fishing line every 5 seconds. He estimates the distance between the crests to be 1.5 meters and estimates that the crest of the waves are 0.5 meters above the troughs. Using this data, determine the amplitude and speed of the waves.

amplitude = 0.5 m 4 2 = 0.25 m

light waves in a laser beam interact and act as one wave. This light is called

coherent light

a ___ lens refracts light and focuses it inward to a focal point

concave

a___ mirror is a mirror shaped like the inside of a spoon

concave mirror

a simple refracting telescope has

convex mirror

As the wavelength increases , the frequency

decreases

shadows have blurry edges because of

diffraction

Reflected sound waves are called___.

echoes

Light is a kind of___ and can therefore travel though matter and space.

electromagnetic wave

Waves that don't require a medium are

electromagnetic waves

electromagnetic waves transmit

energy

waves transfer

energy

a person who has ___ has trouble reading a book

farsightedness

The doppler effect will cause the siren to sound___.

higher

if you move a___ you can see a 3d shape

hologram

___ is a wave interaction that occurs when two or more waves overlap and combine

interference

Which of the following parts of the eye refracts light

lens

The___ of a sound wave depends on its amplitude.

loudness

a vision problem that happens when light is focused in front of the retina is

nearsightedness

this book is a ___ object.

opaque

A technological device that can be used to see sound waves is a___.

oscilloscope

___ is the transfer of energy by electromagnetic waves

radiation

prisms produce the colors of the rainbow through

refraction

you can see yourself in a mirror because of

regular reflection

Resonance can happen when an object vibrates at another object's

resonant frequency, fundamental frequency, second overtone freuqnecy

Two different instruments playing the same note sound different because of___.

sound quality

During constructive interference

the amplitude increases

when a wave enters a new medium

the wave speed changes

Calculate the time it takes for light from the sun to reach mercury. mercury is 54, 900, 000 km away from the sun.

time = distance speed time; time = 54,900,000 km 300,000 km/s; time = 183 s (or 3.05 min)

objects that transmit light easily are

translucent

During, ___ light travels though an object

transmission

electromagnetic waves are made of

vibrating electric and magnetic fields

when you look as yourself in a plane mirror, you see a___

virtual image that appears to be behind the mirror