
What is the relation between amplitude of a wave and its intensity?
Answer
513.3k+ views
1 likes
Hint: Energy of wave is proportional to the square of the amplitude of light wave in terms of wave picture of light. The intensity of a wave is equal to the power transferred by the wave per unit area. Hence, energy is proportional to the intensity.
Formula used:
, where E is the energy of the wave and I is the intensity.
Complete step by step answer:
For light waves, the energy of the light wave is proportional to the intensity.
, where E is the energy of the wave and I is the intensity.
…(1)
Also, the intensity of a wave is power transferred per unit area.
We know that power is energy expended per unit time.
Therefore,
, where, A is the area of the wave and t is the time.
Therefore, we can say that.
…(2)
From expression (1) and (2) we can say that.
Or
Hence, our answer is option C.
Additional Information:
This answer is according to the wave picture of light.
According to the particle picture the intensity can be derived from photon flux.
According to De Broglie principle, light as well as matter have dual (wave and particle) nature.
Light consists of electric and magnetic waves, and hence it is called electromagnetic wave.
In photoelectric effect, the more is the intensity, the more is the photocurrent if the energy of light is higher than the work function of the material.
The amplitude for a wave is the maximum value in its sinusoidal deviation.
Just like light electrons are also known to undergo wave phenomena like diffraction and interference.
It is usually not feasible to measure the intensity for visible light, but it is feasible to measure for radio waves.
The electric wave and magnetic wave are perpendicular to each other during the propagation of light.
Note:
Those students who try to solve this question in a hurry can make simple error in observation as we usually don’t see the expression , and can confuse with the expression . So, be alert while solving the question.
Formula used:
Complete step by step answer:
For light waves, the energy of the light wave is proportional to the intensity.
Also, the intensity of a wave is power transferred per unit area.
We know that power is energy expended per unit time.
Therefore,
Therefore, we can say that.
From expression (1) and (2) we can say that.
Or
Hence, our answer is option C.
Additional Information:
This answer is according to the wave picture of light.
According to the particle picture the intensity can be derived from photon flux.
According to De Broglie principle, light as well as matter have dual (wave and particle) nature.
Light consists of electric and magnetic waves, and hence it is called electromagnetic wave.
In photoelectric effect, the more is the intensity, the more is the photocurrent if the energy of light is higher than the work function of the material.
The amplitude for a wave is the maximum value in its sinusoidal deviation.
Just like light electrons are also known to undergo wave phenomena like diffraction and interference.
It is usually not feasible to measure the intensity for visible light, but it is feasible to measure for radio waves.
The electric wave and magnetic wave are perpendicular to each other during the propagation of light.
Note:
Those students who try to solve this question in a hurry can make simple error in observation as we usually don’t see the expression
Latest Vedantu courses for you
Grade 7 | CBSE | SCHOOL | English
Vedantu 7 CBSE Pro Course - (2025-26)
School Full course for CBSE students
₹45,300 per year
Recently Updated Pages
Master Class 11 Business Studies: Engaging Questions & Answers for Success

Master Class 11 Economics: Engaging Questions & Answers for Success

Master Class 11 Accountancy: Engaging Questions & Answers for Success

Master Class 11 Computer Science: Engaging Questions & Answers for Success

Master Class 11 Maths: Engaging Questions & Answers for Success

Master Class 11 English: Engaging Questions & Answers for Success

Trending doubts
Difference Between Prokaryotic Cells and Eukaryotic Cells

1 ton equals to A 100 kg B 1000 kg C 10 kg D 10000 class 11 physics CBSE

One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

1 Quintal is equal to a 110 kg b 10 kg c 100kg d 1000 class 11 physics CBSE

Net gain of ATP in glycolysis a 6 b 2 c 4 d 8 class 11 biology CBSE

Give two reasons to justify a Water at room temperature class 11 chemistry CBSE
