Advertisements
Advertisements
प्रश्न
Advertisements
उत्तर
The electromagnetic radiations of wavelength from 100 Å to 4000 Å are called the ultraviolet radiations.
Detection: If the different radiations from the red part of the spectrum to the violet end and beyond it are made incident on the silver-chloride solution, it is observed that from the red end to the violet, the solution remains almost unaffted. However just beyond the violet end, it first turns violet and finally it becomes dark brown (or black). thus, there exist certain radiations beyond the violet end of the spectrum, which are chemically more active than the visible light. Thses radiations are called the ultraviolet radiations.
Two properties of ultraviolet radiation:
1. Ultraviolet radiation can pass through quartz, but they are absorbed by glass.
2. They are usually scattered ny the dust particles present in the atmosphere.
one use of ultraviolet radiation:
in producing, Vitamin D, in food of plans and animals.
APPEARS IN
संबंधित प्रश्न
To which part of the electromagnetic spectrum does a wave of frequency 5 × 1011 Hz belong?
Give a reason for the following:
It is necessary to use satellites for long-distance TV transmission. Why?
Name the subjective property of light related to its wavelength.
(a) Give a list of at least five radiations, in order of their increasing frequencies, which make up the complete electromagnetic spectrum.
(b) Which of the radiation mentioned by you in part (a) has the highest penetrating power.
50% of the X-ray coming from a Coolidge tube is able to pass through a 0.1 mm thick aluminium foil. The potential difference between the target and the filament is increased. The thickness of the aluminium foil that will allow 50% of the X-ray to pass through will be
X-ray from a Coolidge tube is incident on a thin aluminium foil. The intensity of the X-ray transmitted by the foil is found to be I0. The heating current is increased to increase the temperature of the filament. The intensity of the X-ray transmitted by the foil will be
(a) zero
(b) < I0
(c) I0
(d) > I0
Choose the correct option.
The EM wave emitted by the Sun and responsible for heating the Earth’s atmosphere due to greenhouse effect is
What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characteristic of LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb?
Given below in the left column are different modes of communication using the kinds of waves given in the right column.
| A. | Optical Fibre Communication |
P. | Ultrasound |
| B. | Radar | Q. | Infrared Light |
| C. | Sonar | R. | Microwaves |
| D. | Mobile Phones | S. | Radio Waves |
From the options given below, find the most appropriate match between entries in the left and the right column.
Identify the electromagnetic radiation and write its wavelength range, which is used to kill germs in water purified. Name the two sources of these radiations.
