Wave picture of light has failed to explain
(1) photoelectric effect
(2) interference of light
(3) diffraction of light
(4) polarization of light
Wave picture of light has failed to explain
(1) photoelectric effect
(2) interference of light
(3) diffraction of light
(4) polarization of light
Show Hint
photoelectric effect
interference of light
diffraction of light
polarization of light
The Correct Option is A
Solution and Explanation
Step 1: Understanding the Wave and Particle Nature of Light
The wave theory of light successfully explains several optical phenomena such as:
- Interference (superposition of waves),
- Diffraction (bending of waves around obstacles), and
- Polarization (orientation of light waves).
However, the wave theory failed to explain the photoelectric effect, which involves the ejection of electrons from a metal surface when exposed to light.
Step 2: Why Wave Theory Fails for the Photoelectric Effect
According to the wave model:
- Energy is spread out across the wavefront.
- Light of any intensity should eventually eject electrons if given enough time.
However, experimental results show that:
- Electrons are ejected instantaneously, without delay.
- The kinetic energy of emitted electrons depends on the
frequency, not the intensity of light.
- There exists a threshold frequency below which no electrons are ejected, regardless of intensity.
This led to Einstein's particle theory of light, where light is made up of photons, each carrying discrete packets of energy (\( E = h \nu \)).
Top Questions on Waves
- A source at rest emits sound waves of frequency \( 102 \) Hz. Two observers are moving away from the source of sound in opposite directions each with a speed of \( 10\% \) of the speed of sound. The ratio of the frequencies of sound heard by the observers is?
- The path difference between two particles of a sound wave is \( 50 \) cm and the phase difference between them is \( 1.8\pi \). If the speed of sound in air is \( 340 \) m/s, the frequency of the sound wave is?
- The frequency of fifth harmonic of a closed pipe is equal to the frequency of third harmonic of an open pipe. If the length of the open pipe is 72 cm, then the length of the closed pipe is:
- The frequency of sound heard by a stationary observer is \( f_1 \), when the source of sound is approaching the observer with a speed of 10% of the speed of sound. If the same source of sound is moving away from the stationary observer with a speed of 20% of the speed of sound, the frequency of sound heard by the observer is \( f_2 \). Then \( f_1 : f_2 \) is:
- If the tension applied to a string is decreased by 36%, then the fundamental frequency of the transverse waves of the string is:
Questions Asked in TS EAMCET exam
- If \[ f(x) = 3x^{15} - 5x^{10} + 7x^5 + 50\cos(x - 1), \] then \[ \lim_{h \to 0} \frac{f(1 - h) - f(1)}{h^2 + 3h} \] is:
If the function
\[ f(x) = \begin{cases} \frac{(e^x - 1) \sin kx}{4 \tan x}, & x \neq 0 \\ P, & x = 0 \end{cases} \]
is differentiable at \( x = 0 \), then:
- If \[ y = \log \left( x - \sqrt{x^2 - 1} \right), \] then \[ (x^2 - 1)y'' + xy' + e^y + \sqrt{x^2 - 1} = \] evaluates to:
- TS EAMCET - 2024
- Fundamental Theorem of Calculus
If
\[ A = \{ P(\alpha, \beta) \mid \text{the tangent drawn at P to the curve } y^3 - 3xy + 2 = 0 \text{ is a horizontal line} \} \]
and
\[ B = \{ Q(a, b) \mid \text{the tangent drawn at Q to the curve } y^3 - 3xy + 2 = 0 \text{ is a vertical line} \} \]
then \( n(A) + n(B) = \)
- TS EAMCET - 2024
- Fundamental Theorem of Calculus
- Consider the curves \( y = f(x) \) and \( x = g(y) \), and let \( P(x,y) \) be a common point of these curves. If at \( P \), on the curve \( y = f(x) \), \[ \frac{dy}{dx} = Q(x), \] and at the same point \( P \) on the curve \( x = g(y) \), \[ \frac{dx}{dy} = -Q(x), \] then:
- TS EAMCET - 2024
- Geometry