CUET · PHYSICS · PYQ PAPER 2025
Light of frequency \( 8.27 \times 10^{14} \text{ Hz} \) is incident on a metal surface. Electrons with maximum speed \( 6.6 \times 10^5 \text{ m/s} \) are ejected. The threshold frequency for photoemission of electrons will be (given \( h = 6.6 \times 10^{-34} \text{ Js} \), and mass of electron = \( m_e = 9 \times 10^{-31} \text{ kg} \)) :
- A \( 5.30 \times 10^{14} \text{ Hz} \)
- B \( 4.74 \times 10^{14} \text{ Hz} \)
- C \( 3.84 \times 10^{14} \text{ Hz} \)
- D \( 5.94 \times 10^{14} \text{ Hz} \)
Answer & Solution
Correct Answer
(A) \( 5.30 \times 10^{14} \text{ Hz} \)
Step-by-step Solution
Detailed explanation
\( hf = hf_0 + \frac{1}{2} m_e v_{max}^2 \) \( f_0 = f - \frac{m_e v_{max}^2}{2h} \) \( f_0 = 8.27 \times 10^{14} - \frac{9 \times 10^{-31} \times (6.6 \times 10^5)^2}{2 \times 6.6 \times 10^{-34}} \)…
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
- A conducting circular loop is placed in a uniform magnetic field of \( B = 0.5 \text{ T} \), with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at the rate of \( \frac{dr}{dt} = 4 \text{ mm/s} \). When the radius of the loop is \( r = 4 \text{ cm} \), the induced emf in the loop isCUET 2025 Easy
- A concave lens and a convex mirror both are dipped in an oil of refractive index 1.2. The focal length of:CUET 2023 Hard
- If \( \mu_0 \) is the permeability and \( \epsilon_0 \) is the permittivity of free space, then the velocity of light (c) is:CUET 2025 Easy
- The mutual inductance of a pair of solenoid depends :
(A) on their separation
(B) on their relative orientation
(C) on the current flowing
(D) on the number of turns in the solenoids
Choose the correct answer from the options given below:CUET 2023 Hard - An unpolarised light of intensity \( I_0 \) passes through five identical polarisers arranged in such a manner that the transmission axis of each is set at an angle of 30° with respect to its predecessor. The ratio of the intensity of the final emerging light to that of the unpolarised light isCUET 2023 Hard
- Match List-I with List-II
Choose the correct answer from the options given below :List-I List-II A. Reactance (I) LCR Circuit B. Inductance (II) \(\frac{\rho l}{\pi r^2}\) C. Capacitance (III) \(\frac{\varepsilon_0 A}{d}\) D. Impedance (IV) \(\frac{\mu_0 N^2 A}{L}\) CUET 2023 Easy
More PYQs from CUET
- Which phenomenon occurs when an electric field is applied to a colloidal solution and electrophoresis is prevented?
(A) \quad Reverse osmosis takes place
(B) \quad Electroosmosis takes place
(C) \quad Dispersion medium begins to move in an electric field
(D) \quad Dispersion medium becomes stationary
Choose the correct answer from the options given below :CUET 2023 Easy - Match the Matrix in List - I with its Adjoint's Determinant in List - II.
List - I (Matrix A) :
Choose the correct answer from the options given below:LIST 1 LIST 2 (A) \(\left[\begin{array}{ll}3 & 1 \\ 4 & 2\end{array}\right]\) (I) 9 (B) \(\left[\begin{array}{cc}5 & -1 \\ 4 & 2\end{array}\right]\) (II) 8 (C) \(\left[\begin{array}{cc}6 & -1 \\ 2 & 1\end{array}\right]\) (III) 14 (D) \(\left[\begin{array}{ll}4 & 1 \\ 3 & 3\end{array}\right]\) (IV) 2 CUET 2025 Medium - The electric field amplitude of an electromagnetic wave is \(100 N C ^{-1}\) and its frequency is 50 MHz . What is the magnitude of wave vector \(k\), (given speed of electromagnetic wave is \(3 \times 10^8 m s ^{-1}\) )CUET 2023 Medium
- Which of the following statements are INCORRECT regarding biodiversity:
A. Rauwolfia vomitoria possess the species diversity in terms of potency and concentration of the active chemical reserpine.
B. Western Ghats have a greater amphibian species diversity than the Eastern Ghats.
C. India has more than 60,000 genetically different strains of rice and 10,000 varieties of mango.
D. India has greater ecosystem diversity than Norway.
Choose the correct answer from the options given below:CUET 2023 Medium - Match List-l with List-ll
List-l (Organisms) List-II (Types of
interaction)(A) Barnacles Balanus and Chathamalus in the
intertidal area(I) Mutualism (B) Orchid growing on a mango branch (II) Competition (C) Plants and herbivores (III) Predation (D) Mycorrhiza between fungi and roots of higher
plants(IV) Commensalism
Choose the correct answer from the options given below:CUET 2025 Hard - The least positive integer \(x\) satisfying \(28=x(\bmod 6)\) is :CUET 2023 Medium