Advertisements
Advertisements
Question
Solve the numerical problem.
The speed of light is 3 × 108 m/s. Calculate the frequency of red light of a wavelength of 6.5 × 10−7 m.
Advertisements
Solution
Given: c = 3 × 108 m/s, λ = 6.5 × 10–7 m
To find: Frequency (ν)
Formula: c = νλ
Calculation: From formula,
ν = `"c"/λ=(3xx10^8)/(6.5xx10^-7)` = 4.6 × 1014 Hz
The frequency of red light is 4.6 × 1014 Hz.
APPEARS IN
RELATED QUESTIONS
How are infrared waves produced?
What role dose infra-red radiation play in maintain the Earth’s warmth
Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?
What is the range of the wavelength of the following electromagnetic waves?
(a) Gamma rays.
Give the range of wavelength of the electromagnetic waves visible to us.
Name the waves used for taking photographs in dark.
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.
In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?
X-ray and visible light travel at the same speed in vacuum. Do they travel at the same speed in glass?
If the potential difference applied to the tube is doubled and the separation between the filament and the target is also doubled, the cutoff wavelength
50% of the X-rays coming from a Coolidge tube are able to pass through a 0.1 mm thick aluminium foil. If the potential difference between the target and the filament is increased, the fraction of the X-rays passing through the same foil will be
Cutoff wavelength of X-rays coming from a Coolidge tube depends on the
(a) target material
(b) accelerating voltage
(c) separation between the target and the filament
(d) temperature of the filament.
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.)
-
- Calculate the speed of the wave.
- Name the medium through which it is traveling.
Name the radiation which can be detected by thermopile.
Name the radiation of the electromagnetic spectrum which is used for the following:
Radar and Give the frequency range.
Name two sources of ultraviolet radiation.
State two properties of infrared radiations which differ from visible light.
Give one use of electromagnetic radiation in Ultraviolet radiation.
Choose the correct option.
Earth’s atmosphere is richest in
Answer briefly.
Does an ordinary electric lamp emit EM waves?
An e.m. wave exerts pressure on the surface on which it is incident. Justify.
The fundamental frequency of an open organ pipe is 300 Hz. The first overtone of this pipe has same frequency as first overtone of a closed organ pipe. If speed of sound is 330 m/s, then the length of closed organ pipe is:
If λv, λx and λm Am represents the wavelength of visible light, x-ray and microwaves respectively, then ______.
Identify the electromagnetic wave whose wavelength range is from about 10-3 m to about 10-1 m. Write one use of this.
Identify the part of the electromagnetic spectrum which:
- produces the heating effect.
- is absorbed by the ozone layer in the atmosphere.
- is used for studying crystal structure.
Write any one method of the production of each of the above radiations.
Name one radiation having the wavelength longer than the wavelength of these radiations.
What happens when an electron collides with a positron?
