Advertisements
Advertisements
Question
The magnetic field of a beam emerging from a filter facing a floodlight is given by B0 = 12 × 10–8 sin (1.20 × 107z – 3.60 × 1015t) T. What is the average intensity of the beam?
Advertisements
Solution
The standard equation of magnetic field can be expressed as B = B0 sin ωt.
We are given equation B = 12 × 10–8 sin (1.20 × 107z – 3.60 × 1015t) T.
On comparing this equation with standard equation, we get
B0 = 12 × 10–8 T
The average intensity of the beam
`I_(av) = 1/2 B_0^2/mu_0 * c = 1/2 xx ((12 xx 10^-8)^2 xx 3 xx 10^8)/(4pi xx 10^-7)`
= 1.71 W/m2
APPEARS IN
RELATED QUESTIONS
A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
State an additional use of the X-rays waves
What do you understand by the statement, "Electromagnetic waves transport momentum"?
Name the subjective property of light related to its wavelength.
Name the rays or waves of highest frequency .
An electromagnetic wave has a frequency of 500 MHz and a wavelength of 60 cm Calculate the velocity of the wave.
The wavelength of X-rays is 0.01 Å. Calculate its frequency. State the assumption made, if any.
What potential difference should be applied across an X-ray tube to get X-ray of wavelength not less than 0.10 nm? What is the maximum energy of a photon of this X-ray in joule?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The Kα and Kβ X-rays of molybdenum have wavelengths 0.71 A and 0.63 A respectively. Find the wavelength of Lα X-ray of molybdenum.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Write the range of the wavelength of the following electromagnetic radiations:
(a) Infrared rays
(b) Ultraviolet rays
(c) γ -rays
Write one use of each of the above.
-
- Calculate the speed of the wave.
- Name the medium through which it is traveling.
Name three radiations and their wavelength range which are invisible and beyond the violet end of the visible spectrum.
Identify the part of the electromagnetic spectrum used in
(i) radar and
(ii) eye surgery. Write their frequency range.
Give one use of electromagnetic radiations in Infrared radiation.
Name the radiations used for the detection of fracture in bones.
Answer briefly.
Give two uses of ultraviolet rays.
Light of wavelength `3500A` is incident on two metals A and B whose work functions are 3.2 eV and 1.9 eV respectively. Which metal will emit photoelectrons?
The ozone layer absorbs
