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Delhi Police Constable Exam Model Paper 4
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© examsnet.com
Question : 27
Total: 100
Which one of the following waves are used by the common TV remote control?
Lasers
Radio waves
Ultrasonic waves
Infrared waves
Validate
Solution:
The correct answer is option4i.
eInfrared waves.
Infrared wave is an electromagnetic wave.
It was discovered by
Willam Herschel.
Infrared waves are used by the common
TV remote control.
Waves used in distant photography.
Invisible to the human eye.
Most of the thermal radiation emitted by objects near room temperature is infrared.
Used for target acquisition purposes in military and civilian applications.
Wavelength:
700 nanometers to 1 millimeter.
The
heat of the sunlight
is due to Infrared rays.
Radio waves
● Electromagnetic wave with
maximum wavelength.
● Wavelength: 1 meter to 100,000 km
● Waves used in radio and television broadcasting.
●Radio waves were first predicted by
James Clerk Maxwell.
Lasers
●LASER stands for Light Amplification by Stimulated Emission of Radiation.
●Source of intense monochromatic light.
Discovered by
Theodore Maiman.
●Used in medical fields to perform minute operations.
Ultrasonic waves
● Sound waves
produced by Bats.
●Sound higher than 20000 Hz.
●Inaudible sound for humans.
●Used in ultrasound scanning.
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