3453

Physics Electromagnetic Waves Level: High School

The eye is most sensitive to light of wavelength 5.545 x 10^-7 m, which is in the green-yellow region of the visible electromagnetic spectrum . The speed of light is 3 x 10^8 m/s . What is the frequency of light ? Answer in units of Hz .Your answer must be within +-0.1% .

3452

Physics Electromagnetic Waves Level: High School

Consider a beam of electromagnetic radiation , which is traveling along the positive z direction . Its average intensity is 316 W/m^2 . The permeability of free space is 1.257 x 10^-6 N/A^2 and the speed of light is 3 x 110^8 m/s . What is its maximum electric field ? Answer in units of N/C . What is the pressure on a surface which is perpendicular to the beam and is total reflective ? What is the maximum magnetic field ?

Consider the electromagnetic wave pattern as shown in the figure at Ã¢â‚¬Å“click hereÃ¢â‚¬Â . The direction in which the wave is traveling is ?

a) from-right to left

b) from left-to-right

c) Undetermined ,since the figure shows a standing wave

##### Question Diagram

3451

Physics Electromagnetic Waves Level: High School

At what distance from a 50 W electromagnetic wave point source (like a light bulb) is he amplitude of the electric field 24 V/m ? micro 0 c = 376.991 ohm .

3442

Physics Electromagnetic Waves Level: High School

In the diagram on the right , the electric field vector points upwards and the magnetic field vector points out of the page directly at you . This electromagnetic wave is traveling .

a) upwards

b) downwards

c) to the right

d) into the page

2662

Physics Electromagnetic Waves Level: High School

The speed of light in vacuum is --------

299, 792, 458 km/s

299, 792, 458 km/s

399, 462, 798 km/s

399, 462, 798 km/s

299, 792, 458 km/s

2647

Physics Electromagnetic Waves Level: High School

Radio waves travel at the speed of light. The LORAN C navigation system (which has a transmitter near Searchlight , Nevada) operates on the relatively low radio frequency of 100 . KHz )

a) What is the wavelength of the LORAN C signal ?

b) For comparison , what is the wavelength of the X-band (8.00 GHz = 8.00 x 10^9 Hz) telemetry signals which NASA uses to bring back picture of Saturn and its moons from the Cassini spacecraft ? ( The radio spectrum covers a wide range of wavelength)

2600

Physics Electromagnetic Waves Level: High School

A possible means of space flight is to place a perfectly reflecting aluminized sheet into Earthâ€™s orbit and use the light from the Sun to push this solar sail . Suppose a sail of area 6.00 x 10^4 m^2 and mass 6000 kg is placed in orbit facing the sun . The solar intensity of 1380 W/m^2 .

a) What force is exerted on the sail ?

b) What is the sailâ€™s acceleration ?

c) How long does it take the sail to reach the Moon , 3.84 x 10^8 m away ? Ignore all gravitational effect and assume that the acceleration calculated in part b remains constant

2582

Physics Electromagnetic Waves Level: High School

Light is an example of an electromagnetic wave .

a) Why is it called electromagnetic ?

b) If the light wave were generated at a frequency of 5.6 x 10^14 Hz , what would be its wavelength ?

c) If a polarizer is placed in front of the beam of light what would happen ? Explain why this occurs .

d) Radiation of light can be determined by the Stephen-Bolzmann equation .

i) What does this equation predict will happen if the temperature of the light source is increased ?

ii) In what units would delta Q / delta t be expressed ?

iii) What does the symbol e represent in this equation ?

2434

Physics Electromagnetic Waves Level: High School

The energy density of electromagnetic radiation is some region of space is 10^-12 J/m^3 . Assume that the radiation has wavelength in the middle of the visible range , 550 nm . What is the photon density ?

2433

Physics Electromagnetic Waves Level: High School

Dual Nature

Find the energy of a photon for each of the following cases .

a) a microwave of wavelength 3 cm .

b) blue light of wavelength 420 nm .

c) a radio wave of frequency 1070 kHz .

d) an x-ray of wavelength of 0.1 nm .

2242

Physics Electromagnetic Waves Level: High School

The average intensity of sunlight reaching the earth is 1.390 W/m^2 with an electric field whose rms value is E = 720 N/C . A charge of 2.6 x 10^-8C is placed in the path of this electromagnetic wave .

a) What is the magnitude of the electric force the charge experiences ?

b) If the charge is moving at a speed of 3.7 x 10^4 m/s , what is the magnitude of the magnetic force that the charge could experience ?

2095

Physics Electromagnetic Waves Level: High School

Which one of the following is not a common use of microwave ?

a) cooking

c) medical imaging

d) communication

medical imaging

2094

Physics Electromagnetic Waves Level: High School

Type of EM waves having the highest frequency in this list is .

a) ultraviolet

b) infrared

c) x-rays

d) microwave

e) gamma rays

e) gamma rays

2093

Physics Electromagnetic Waves Level: High School

The greenhouse effect occurs because .

a) Low frequency EM waves are reflected from the atmosphere .

b) High frequency EM waves are reflected from the atmosphere .

c) The ozone layer absorbs ultraviolet light .

d) Carbon dioxide in the atmosphere absorbs IR emission re-radiated from the earthâ€™s .

e) None of the above .

Carbon dioxide in the atmosphere absorbs IR emission re-radiated from the earthâ€™s .

1144

Physics Electromagnetic Waves Level: High School

An electromagnetic wave has an electric field with peak value 250 N/C . What is the average intensity of the wave ?

a. 0.66 W/m^2

b. 0.89 W/m^2

c. 83 W/m^2

d. 120 W/m^2

e. 170 W/m^2

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