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Question : 15
Total: 29
(a) How are electromagnetic waves produced?
(b) How do you convince yourself that electromagnetic waves carry energy and momentum ?
OR
(a) Arrange the following electromagnetic waves in the descending order of their wavelengths:
(i) Microwaves
(ii) Infra-red rays
(iii) Ultra-violet radiation
(iv) Gamma rays
(b) Write one use each of any two of them.
(b) How do you convince yourself that electromagnetic waves carry energy and momentum ?
OR
(a) Arrange the following electromagnetic waves in the descending order of their wavelengths:
(i) Microwaves
(ii) Infra-red rays
(iii) Ultra-violet radiation
(iv) Gamma rays
(b) Write one use each of any two of them.
Solution:
(a) Accelerating electric charge produces electromagnetic waves.
(b) When electromagnetic wave of suitable frequency on incident on photoelectrons come out. So, electromagnetic waves must have energy and momentum so that it can kick off photoelectrons from its shell. Thus I am convinced.
OR(a) Arranged in descending order:
Microwave, Infrared, Ultraviolet, Gamma-rays
(b) Use of microwave: Used in RADAR system.
Use of Infrared: Used in night-photography.
(b) When electromagnetic wave of suitable frequency on incident on photoelectrons come out. So, electromagnetic waves must have energy and momentum so that it can kick off photoelectrons from its shell. Thus I am convinced.
OR(a) Arranged in descending order:
Microwave, Infrared, Ultraviolet, Gamma-rays
(b) Use of microwave: Used in RADAR system.
Use of Infrared: Used in night-photography.
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