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# Intensity

### Waves/Superposition

Three identical loudspeakers play a 170 Hz tone in a room where the speed of sound is 340 m/s. You are standing 4 m in front of the middle speaker. At this point, the amplitude of the wave from each speaker is "a". a) What is the amplitude at this point? b) How far must speaker 2 be moved to the left to produce a maximum a

### Lingt: Intensity and energy

You are standing 2.2 m from a 150 W light bulb. (a) If the pupil of your eye is a circle 5.1 mm in diameter, how much energy enters your eye per second? [Assume that 5.0% of the light bulb's power is converted to light.] (b) Repeat part (a) for the case of a 2.2 mm diameter laser beam with a power of 0.66 mW.

### Interference of light: Wedge shaped film, No. of fringes.

Considering Otto Wiener's experiment in monochromatic light of wavelength 550nm, if the film plane is angle at 1 degree to the reflecting surface, determine the number of bright bands per centimeter that will appear on it.

### Interference of Waves: Maximum intensity again

Two 1.0M-Hz radio antennas emitting in-phase are separated by 600m along a north-south line. A radio receiver placed 2.0 km east is equidistant from both the transmitting antennas and picks up a fairly strong signal. How far north should that receiver by moved if it is again to detect a signal nearly as strong. non-paraxial

### Intensity of sound

By what amount does the intensity level decrease when you triple your distance from a source of sound?

### Polarization

Completely polarized light is passed through a polarizing sheet. The light that passes though has an intensity of 50% of the incident beam. The angle between the direction of the polarization of the incident beam and the direction of the polarization of the sheet must be what?

### Interference of light waves: Young's double slit experiment.

Imagine doing Young's two slit interference experiment with an average of one photon per second incident on the slits. If you cover one slit with your thumb every other second, will there be interference ? Why ? What's going on ? What pattern will you see if you average for a long time ?

### Frequency of Bi-color LED

A bi-color LED alternates so that the color red emits at 60Hz and the color green emits at 60 Hz, so that visually it appears yellow. What frequency would it blink if you viewed it through a yellow filter? What frequency would it blink if you viewed it through a green filter?

### Point source of light

Consider a point source of light. How would the intensity of light vary with distance from the source according to a) wave theory and b) particle or photon theory? Explain.

### How Sound Intensity Varies with Distance from the Source

A point source of sound that emits uniformly in all directions is located in the middle of a large, open field. The intensity at Brittany's location directly north of the source is twice that at Phillip's position due east of the source. What is the distance between Brittany and Phillip if Brittany is 10.0 m from the source?

### Sound Intensity of Twenty Violins Playing Simultaneously

Twenty violins playing simultaneously with the same intensity combine to give an intensity level of 82.5 dB. (a) What is the intensity level of each violin? (b) If the number is increased to 40, will the combined intensity level be more than, less than, or equal to 165 dB? explain

### Sound Intensity Relations

Sound 1 has an intensity of 380.0 W/m^2. Sound 2 has an intensity level that is 2.5 dB greater than the intensity level of sound 1. What is the intensity of sound 2?

### Sound Intensity Levels

The distance to a point source is tripled. (a) By what factor does the intensity decrease? (b) By what amount does the intensity level decrease?

### What is the intensity of sound at a given point?

The intensity of sound at a given point is measured to be 0.0005 W/m^2. What is the decibel level of the sound? a. 97 db b. 87 db c. 90 db d. 55 db

### Converging Lenses, Diffraction Grating, Reflection & Polarizing

See attachment for figures. 1) Two converging lenses with focal lengths of 40cm and 20cm are placed 10cm apart. A 2cm tall object is 15cm from the 40cm focal length lens. a) Use ray tracing to locate the image of the lens combination. b) Is the image real or virtual? Is it upright or inverted? c) Calculate the exact locati

### What is the sound intensity in the room?

If I have the television on and the sound level is 60 dB, then my wife starts the vacuum which is 74 dB, then the baby starts crying at 78 dB, what is the total sound level in the room? And what is the total intensity?

### Child Screaming Intensity and Analysis

A mother hears a child scream from across the room, 23 feet away. The sound pressure level is 72dB. When she holds the child on her shoulder, her ear is 3 inches from the screams. Using the decibel chart, about how long until damage to her hearing occurs if the child continues screaming? http://www.gcaudio.com/resources/howto

### Polarization of Light Waves

Unpolarized light passes through two polaroid sheets. The axis of the first is vertical, and that of the second is at 26.0° to the vertical. What fraction of the initial light is transmitted?

### Intensity of Light and Distance from Source

The illumination, I in luxes of a surface d meters from a light source given by I=kd^(-2) where k is a constant based on the intensity of the light source. (a. Solve for k if we know that I = 750 luxes at a distance of 2 meters from the light source. k = 3000) This is the question I need help with!! B. IF OUR SOLAR POWER

### Intensity of a light bulb

Hi. Can someone please help me with this conceptual question? Consider a circuit consisting of a light bulb and an inductor. If the frequency of the generator is increased, does the intensity of the light bulb increase, decrease, or stay the same? Explain. Thank you.

### Minimizing question

The illumination at a point is inversely proportional to the square of the distance of the point from the light source and directly proportional to the intensity of the light source. If two light sources are 30 feet apart and their intensities are 70 and 50 respectively, at what point will the sum of their illumination be minimu

### Dependent and independent variables

Suppose you were interested in determining the effect of lighting on the morale of your employees. How would you go about obtaining data for your research? What would be your dependent and independent variables? How would you determine the ideal amount of lighting? Please use a real life situation, like an Insurance office

### Calculate the sound level of a brass band given intensity.

If the sound intensity of a brass band is 2.5x10^-2 W/m^2, what is the sound level of the band?

### Ratio of final sound intensity after amplifier increases level

The volume control on a stereo amplifier is adjusted so the sound intensity level increases from 23 to 61 dB. What is the ratio of the final sound intensity to the original sound intensity?

### Radius of a concave mirror using the intensity of sunlight

The intensity of sunlight is 1.00 kW/m^2. A highly reflective concave mirror is pointed at the sun to produce a power of at least 350 W at the image. a) Find the radius r of the circular mirror. b) Suppose the light intensity is to be at least 120 kW/m^2. Find the relationship between r (the radius) and R (the curvature) of t