Advertisements
Advertisements
प्रश्न
Answer briefly.
Give two uses of ultraviolet rays.
Advertisements
उत्तर
Uses:
- Ultraviolet rays destroy germs and bacteria and hence they are used for sterilizing surgical instruments and for purification of water.
- Used in burglar alarms and security systems.
- Used to distinguish real and fake gems.
APPEARS IN
संबंधित प्रश्न
What physical quantity is the same for X-rays of wavelength 10−10 m, red light of wavelength 6800 Å and radiowaves of wavelength 500 m?
Optical and radio telescopes are built on the ground but X-ray astronomy is possible only from satellites orbiting the earth. Why?
Name the phenomenon which shows the quantum nature of electromagnetic radiation.
What is the range of the wavelength of the following electromagnetic waves?
(a) Gamma rays.
What is the range of the wavelength of the following electromagnetic waves?
(a)X-rays,
Name two electromagnetic waves of frequency smaller than that of violet light. State one use of each.
Consider a photon of a continuous X-ray coming from a Coolidge tube. Its energy comes from
The figure shows the intensity-wavelength relations of X-rays coming from two different Coolidge tubes. The solid curve represents the relation for the tube A in which the potential difference between the target and the filament is VA and the atomic number of the target material is ZA. These quantities are VB and ZB for the other tube. Then,
Consider a photon of continuous X-ray and a photon of characteristic X-ray of the same wavelength. Which of the following is/are different for the two photons?
Iron emits Kα X-ray of energy 6.4 keV. Calculate the times taken by an iron Kα photon to cross through a distance of 3 km.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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 short-wavelength limit shifts by 26 pm when the operating voltage in an X-ray tube is increased to 1.5 times the original value. What was the original value of the operating voltage?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
An X-ray tube operates at 40 kV. Suppose the electron converts 70% of its energy into a photon at each collision. Find the lowest there wavelengths emitted from the tube. Neglect the energy imparted to the atom with which the electron collides.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered Infra-red waves
Identify the part of the electromagnetic spectrum used in (i) radar and (ii) eye surgery. Write their frequency range.
How will you investigate the existence of the radiation beyond the red and violet extremes of the spectrum?
State two properties of infrared radiations which differ from visible light.
Give one use of electromagnetic radiations in Infrared radiation.
Answer briefly.
Give two uses of radio waves.
Solve the numerical problem.
Calculate the wavelength in nm of an X-ray wave of frequency 2.0 × 1018 Hz.
An electron beam is accelerated by a potential difference V to hit a metallic target to produce X-rays. It produces continuous as well as characteristic X-rays. If λmin is the smallest possible wavelength of X-ray in the spectrum, the variation of log λmin with log V is correctly represented in:
For television broadcasting, the frequency employed is normally
If λv, λx and λm Am represents the wavelength of visible light, x-ray and microwaves respectively, then ______.
All components of the electromagnetic spectrum in a vacuum have the same ______
Why does microwave oven heats up a food item containing water molecules most efficiently?
In uranium (Z = 92) the K absorption edge is 0.107 Å and the Kα line is 0.126 Å, and the wavelength of the L absorption edge is ______.
Which is the correct ascending order of wavelengths?
What happens when an electron collides with a positron?
Name two electromagnetic waves of wavelength smaller than that of violet light.
