Advertisements
Advertisements
Question
An e.m. wave exerts pressure on the surface on which it is incident. Justify.
Solution
An e.m. wave carries momentum with itself and is given by
P = `"Energy of wave (U)"/"Speed of the wave (c)"`
= `"U"/"c"`
when it is incident upon a surface it exerts pressure on it.
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?
In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?
Why is exposure to X-rays injurious to health but not exposure to visible light, when both are electromagnetic waves?
For harder X-rays,
(a) the wavelength is higher
(b) the intensity is higher
(c) the frequency is higher
(d) the photon energy is higher.
The Kβ X-rays from certain elements are given below. Draw a Moseley-type plot of √v versus Z for Kβ radiation.
| Element | Ne | P | Ca | Mn | Zn | Br |
| Energy (keV) | 0.858 | 2.14 | 4.02 | 6.51 | 9.57 | 13.3 |
Two waves A and B have wavelength 0.01 Å and 9000 Å respectively.
Name the two waves. compare the speeds of these waves when they travel in vacuum.
Name two sources of infrared radiation.
Name the radiations used for the detection of fracture in bones.
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?
Write two uses of the following radiation.
Gamma rays
