UNIT
5 – ELECTROMAGNETIC WAVES
2025
1.
(i) Name the
electromagnetic wave travelling from the satellite to the dish antenna shown in
the image above.
(ii) If the wavelength of
an electromagnetic wave is 6 nm, what is its frequency?
2024
2. (i)
Name the electromagnetic radiation whose frequency is 1011 Hz.
(ii) What is the speed of radio waves
in vacuum?
2023
3. (i)
State how vectors E,B and c are oriented in an electromagnetic wave.
(ii) Name the electromagnetic
wave/radiation which is used to study crystal structure.
2022
4. Consider
four electromagnetic radiations namely infrared radiations, ultraviolet
radiations, micro waves and light. Which one of these has maximum frequency?
(a) infrared radiations (b) ultraviolet radiations
(c) micro-waves (d) light
5. Which
one of the following is used to detect infrared radiations?
(a) Photocell (b) Fluorescent screen
(c) Ionization chamber (d) Thermopile
6. Which
one of the following is used to study crystal structure of a crystalline salt?
(a) UV rays (b) X rays
(c) Micro-waves (d) Radio waves
7. Relaxation
time is
(a) the time interval between number
of collisions of a free electron in a conductor.
(b) the average time interval between
two successive collisions of a free electron with metallic ions in a conductor.
(c) the time interval between number
of collisions of metal ions in a conductor.
(d) the time interval between
collision of free electrons with each other
2020
8. (i)
State any one use of infrared radiations.
(ii) State any one source of
ultraviolet radiations.
2019
9. State
any two properties of microwaves.
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