Advertisements
Advertisements
Question
Give any two uses of infrared waves.
Advertisements
Solution 1
For therapeutic purposes and long distance photography.
Solution 2
- TV Remote Controls: IR LEDs are used to transmit encoded signals to electronic devices.
- Physical Therapy: IR lamps are used to treat muscular strains and provide warmth to tissues.
- Night Vision: IR sensors are used in goggles and cameras to detect heat signatures in the dark.
Notes
Students can refer to the provided solutions based on their preferred marks.
APPEARS IN
RELATED QUESTIONS
Give a reason for the following:
Long-distance radio broadcasts use short-wave bands. Why?
State the approximate range of wavelength associated with visible light.
The Kα X-rays of aluminium (Z = 13) and zinc (Z = 30) have wavelengths 887 pm and 146 pm respectively. Use Moseley's law √v = a(Z − b) to find the wavelengths of the Kα X-ray of iron (Z = 26).
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
A free atom of iron emits Kα X-rays of energy 6.4 keV. Calculate the recoil kinetic energy of the atom. Mass of an iron atom = 9.3 × 10−26 kg.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
The stopping potential in a photoelectric experiment is linearly related to the inverse of the wavelength (1/λ) of the light falling on the cathode. The potential difference applied across an X-ray tube is linearly related to the inverse of the cutoff wavelength (1/λ) of the X-ray emitted. Show that the slopes of the lines in the two cases are equal and find its value.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
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 three radiations and their wavelength range which are invisible and beyond the violet end of the visible spectrum.
Light of wavelength `3500A` is incident on two metals A and B whose work functions are 3.2 eV and 1.9 eV respectively. Which metal will emit photoelectrons?
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:
Why does microwave oven heats up a food item containing water molecules most efficiently?
