MHT CET · Physics · Dual Nature of Matter
Photoelectrons are emitted from a photosensitive surface for the light of wavelengths \(\lambda_{1}=360 \mathrm{~nm}\) and \(\lambda_{2}=600 \mathrm{~nm} .\) What is the ratio of work functions
for lights of wavelength \({ }^{\prime} \lambda_{1}{ }^{\prime}\) to \(\lambda_{2}{ }^{\prime}\)?
- A \(6: 1\)
- B \(1: 6\)
- C \(5: 3\)
- D \(3: 5\)
Answer & Solution
Correct Answer
(C) \(5: 3\)
Step-by-step Solution
Detailed explanation
\(\frac{h c}{\lambda_{1}}-\phi_{1}=\mathrm{KE} \quad \lambda_{1}=360 \mathrm{~nm}=360 \times 10^{-9} \mathrm{~m}\)
\(\frac{\mathrm{hc}}{\lambda_{2}}-\phi_{2}=\mathrm{KE} \quad\lambda_{2}=600 \mathrm{~nm}=600 \times 10^{-9} \mathrm{~m}\)
\(\frac{h c}{\lambda_{1}}=\phi_{1} \quad \quad \phi \propto \frac{1}{\lambda}\)
\(\therefore \frac{\phi_{1}}{\phi_{2}}=\frac{\lambda_{2}}{\lambda_{1}}=\frac{600}{360}=\frac{10}{6}=\frac{5}{3}\)
\(\frac{\mathrm{hc}}{\lambda_{2}}-\phi_{2}=\mathrm{KE} \quad\lambda_{2}=600 \mathrm{~nm}=600 \times 10^{-9} \mathrm{~m}\)
\(\frac{h c}{\lambda_{1}}=\phi_{1} \quad \quad \phi \propto \frac{1}{\lambda}\)
\(\therefore \frac{\phi_{1}}{\phi_{2}}=\frac{\lambda_{2}}{\lambda_{1}}=\frac{600}{360}=\frac{10}{6}=\frac{5}{3}\)
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- In a diffraction pattern due to single slit of width ' \(a\) ', the first minimum is observed at an angle \(30^{\circ}\) when light of wavelength \(5000 Å\) is incident on the slit. The first secondary maximum is observed at an angle \(\left[\sin 30=\frac{1}{2}\right]\)MHT CET 2024 Easy
- A rectangular block of surface area A emits energy E per second at \(27^{\circ} \mathrm{C}\). If length and breadth is reduced to half of initial value and temperature is raised to \(327^{\circ} \mathrm{C}\) then energy emitted per second becomesMHT CET 2025 Medium
- A transistor has a voltage gain 'A'. If the amount ' \(\beta A^{\prime}\) of its output is appl put of the transistor, then the transistor becomes oscillator whereMHT CET 2020 Easy
- A pipe closed at one end length \(0.8 \mathrm{~m}\). At its open end a \(0.5 \mathrm{mlong}\) uniform string is vibrating in its second harmonic and it resonates with the fundamental frequency of the pipe. If the tension in the wire in \(50 \mathrm{~N}\) and the speed of sound is \(320 \mathrm{~m} / \mathrm{s}\), the mass of the string used isMHT CET 2022 Hard
- The lengths of the two organ pipes open at both ends are 'L' and \(\left(L+L_1\right)\). If they are sounded together, the beat frequency will be ( \(\mathrm{v}=\) velocity of sound in air)MHT CET 2025 Medium
- A parallel plate capacitor with plate area \(A\) and plate separation \(d\) is charged by constant current I. A plane surface of area \(\mathrm{A} / 2\), parallel to the plates is drawn simultaneously between the plates. The displacement current through this area isMHT CET 2025 Medium
More PYQs from MHT CET
- Light of wavelength \(\lambda\) which is less than threshold wavelength is incident on a photosensitive material. If incident wavelength is decreased so that emitted photoelectrons are moving with same velocity then stopping potential willMHT CET 2016 Medium
- Lorenz magnetic force is acting on a particle of charge \(q\) moving with velocity \(\vec{V}\) in a magnetic field \(\vec{B}\). The work done by this force on the charged particle isMHT CET 2025 Easy
- Negation of the statement ' Horses have wings if and only if crows have tails. ' isMHT CET 2024 Easy
- A ray of light is incident at \(60^{\circ}\) on one face of a prism of angle \(30^{\circ}\) and the emergent ray makes \(30^{\circ}\) with the incident ray. The refractive index of the prism is \(\left(\sin 30^{\circ}=0 \cdot 5, \sin 60^{\circ}=\sqrt{3} / 2\right)\)MHT CET 2024 Easy
- The self-inductance \(L\) of a solenoid of length \(\lambda\) and area of crosssection \(A\) with a fixed number of turns \(N\) increases asMHT CET 2022 Easy
- Calculate \(\mathrm{E}_{\text {cell }}^{\circ}\) if the equilibrium constant for following reaction is \(1.2 \times 10^6\).
\(
2 \mathrm{Cu}_{(\mathrm{aq})}^{+} \longrightarrow \mathrm{Cu}_{(\mathrm{aq})}^{++}+\mathrm{Cu}_{(\mathrm{s})}
\)MHT CET 2023 Easy