Dual Nature of Radiation and Matter

32 solved questions from Class 12 Physics, each with the full working. Tap any question to see the step-by-step solution.

• 1 What is the fundamental law or governing principle of 'Dual Nature of Radiation and Matter' in Class 12 Physics? medium MCQ Fundamental Physical Law
• 2 What is the SI unit and dimensional formula for the key physical quantity studied in 'Dual Nature of Radiation and Matter'? medium MCQ SI Units & Dimensional Analysis
• 3 How does the field or potential intensity vary with distance r in 'Dual Nature of Radiation and Matter'? medium MCQ Spatial Distance Dependence
• 4 What is the net flux or circulation integral through a closed surface in 'Dual Nature of Radiation and Matter'? medium MCQ Gauss's Theorem & Boundary Integrals
• 5 Why do field lines in 'Dual Nature of Radiation and Matter' never intersect each other? medium MCQ Field Line Properties
• 6 Derive the Compton shift formula and calculate the wavelength change for a photon of initial wavelength 0.15 nm scattered at 180°. What is the scattered wavelength? hard 4 marks Compton scattering wavelength shift
• 7 A metal with work function 2.5 eV is illuminated by light of wavelength 300 nm. What is the maximum kinetic energy of the emitted electrons? medium MCQ 2 marks photoelectric effect maximum kinetic energy
• 8 Using Bohr’s model, determine the energy of the electron in the n=4 level of a hydrogen atom. medium 2 marks Bohr energy levels of hydrogen
• 9 An electron is accelerated through a potential difference of 200 V. Calculate its de Broglie wavelength. easy 1 mark de Broglie wavelength of a moving particle
• 10 In the Davisson–Germer experiment electrons are accelerated through a potential difference of 54 V and a first‑order diffraction maximum is observed at a scattering angle of 50°. Using Bragg's law for electron diffraction, calculate the interplanar spacing d of the crystal. hard 3 marks Electron diffraction and Bragg’s law
• 11 A metal has a work function of 2.5 eV. Which of the following wavelengths of incident light can cause emission of electrons from its surface? easy MCQ 1 mark Photoelectric effect – threshold wavelength
• 12 An electron is accelerated through a potential difference of 150 V and then passes through a double‑slit apparatus whose slit separation is 0.5 μm. The screen is 1 m away from the slits. Find the distance between two consecutive bright fringes on the screen. medium 2 marks De Broglie wavelength and interference of matter waves
• 13 A photon of wavelength 0.71 Å is scattered elastically by a stationary electron at an angle of 120°. Calculate the wavelength of the scattered photon. hard 4 marks Compton effect – wavelength shift
• 14 A 1 g baseball moves with a speed of 30 m s^-1. Estimate its de Broglie wavelength and comment on the observability of wave effects for such a macroscopic object. medium 3 marks Matter wave wavelength for macroscopic objects
• 15 A metal surface has a work function φ = 2.0 eV. Light of wavelength 500 nm shines on it. What is the maximum kinetic energy of the emitted electrons? medium MCQ 3 marks Photoelectric effect – kinetic energy calculation
• 16 Derive the Compton wavelength shift formula and then find the wavelength of a photon that is initially 0.05 nm and scattered elastically by a stationary electron at an angle of 60°. hard 5 marks Compton effect – wavelength shift derivation and calculation
• 17 An electron is accelerated from rest through a potential difference of 100 V. Calculate its de Broglie wavelength in metres. easy 2 marks de Broglie wavelength of accelerated electron
• 18 An X‑ray photon of wavelength 0.10 nm is scattered elastically by an electron at an angle of 120°. Calculate the wavelength of the scattered photon (in nm). medium 3 marks Compton scattering
• 19 Electrons are accelerated through 250 V and then incident on a copper crystal whose lattice planes have spacing 0.20 nm. Using Bragg’s law for electron diffraction, determine the angle at which the first‑order diffraction maximum is observed. hard 4 marks Electron diffraction (Bragg's law)
• 20 A photon of wavelength 0.25 nm is scattered elastically by a stationary electron at an angle of 120°. Find the wavelength of the scattered photon. medium 3 marks Compton wavelength shift
• 21 An electron is accelerated from rest through a potential difference of 300 V. Calculate its de Broglie wavelength in nanometres. easy 2 marks de Broglie wavelength of accelerated electron
• 22 Electrons accelerated through a potential difference of 500 V are incident on a copper crystal whose lattice planes have spacing 0.208 nm. Using Bragg’s law for electron diffraction, determine the angle at which the first‑order diffraction maximum is observed. medium 3 marks Bragg diffraction of electrons
• 23 Metal X has a work function of 2.5 eV. Which of the following wavelengths of incident light can cause electrons to be emitted from its surface? hard MCQ 4 marks Photoelectric threshold wavelength
• 24 A photon of wavelength 0.35 nm is scattered elastically by a stationary electron at an angle of 120°. Find the wavelength of the scattered photon. Which of the following is correct? medium MCQ 2 marks Compton wavelength shift
• 25 A metal surface has a work function of 2.8 eV. Light of wavelength 350 nm is shone on it with a power of 4 mW over an area of 1 cm². Calculate (i) the maximum kinetic energy of the emitted electrons, and (ii) the number of electrons emitted per second. hard 5 marks photoelectric effect calculations
• 26 Electrons are accelerated through 450 V and incident on a graphite crystal whose lattice planes have spacing 0.210 nm. Using Bragg’s law for electron diffraction, determine the angle at which the second‑order diffraction maximum is observed. hard 3 marks Bragg diffraction of electrons
• 27 An electron is accelerated from rest through a potential difference of 250 V. Calculate its de Broglie wavelength in nanometres. easy 1 mark de Broglie wavelength of accelerated electron
• 28 An electron is accelerated from rest through a potential difference of 400 V. What is its de Broglie wavelength in nanometers? easy 1 mark de Broglie wavelength of accelerated electron
• 29 Electrons are accelerated through a potential difference of 600 V and then incident on a nickel crystal whose lattice planes have spacing d = 0.190 nm. Using Bragg’s law for electron diffraction, determine the angle at which the first‑order diffraction maximum occurs. hard 5 marks Electron diffraction, Bragg’s law
• 30 A metal surface has a work function phi = 2.4 eV. Light of wavelength 350 nm is shone on it with a power of 6 mW uniformly over an area of 2 cm^2. medium 3 marks photoelectric effect, work function, photon flux
• 31 A monochromatic photon of wavelength 0.12 nm collides elastically with a stationary electron at an angle of 150^circ. hard 4 marks Compton scattering, wavelength shift formula
• 32 A metal surface has a work function φ=2.7,eV. Light of wavelength 400,nm is shone on it. Which of the following is the maximum kinetic energy of the emitted electrons? medium MCQ 3 marks Einstein photoelectric equation