Science (English Medium) इयत्ता १२ - CBSE Important Questions for Physics

How will the interference pattern in Young's double-slit experiment be affected if the source slit is moved away from the plane of the slits?

How will the interference pattern in Young's double-slit experiment be affected if the phase difference between the light waves emanating from the two slits S₁ and S₂ changes from 0 to π and remains constant?

Monochromatic light of wavelength 600 nm is incident from the air on a water surface. The refractive index of water is 1.33. Find the

1. wavelength,
2. frequency and
3. speed, of reflected and refracted light.

A beam of light consisting of two wavelengths 600 nm and 500 nm is used in Young's double slit experiment. The silt separation is 1.0 mm and the screen is kept 0.60 m away from the plane of the slits. Calculate:

1. the distance of the second bright fringe from the central maximum for wavelength 500 nm, and
2. the least distance from the central maximum where the bright fringes due to both wavelengths coincide.

A ray of light of wavelength 600 nm propagates from air into a medium. If its wavelength in the medium becomes 400 nm, the refractive index of the medium is ______.

In Young's double-slit experiment, the separation between the two slits is d and the distance of the screen from the slits is 1000 d. If the first minima fall at a distance d from the central maximum, obtain the relation between d and λ.

A ray of light travels a distance of 12.0 m in a transparent sheet in 60 ns. The refractive index of the sheet is ______.

In an interference experiment, a third bright fringe is obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain the fifth bright fringe at the same point?

How is a wavefront different from a ray?

Using Huygens’s construction of secondary wavelets draw a diagram showing the passage of a plane wavefront from a denser to a rarer medium. Using it verifies Snell’s law.

Sketch the graphs showing variation of stopping potential with frequency of incident radiations for two photosensitive materials A and B having threshold frequencies v_A > v_B.

(i) In which case is the stopping potential more and why?

(ii) Does the slope of the graph depend on the nature of the material used? Explain.

Calculate the wavelength of radiation emitted when electron in a hydrogen atom jumps from n = `oo` to n = 1.

A proton and an α -particle are accelerated through the same potential difference. Which one of the two has greater de-Broglie wavelength Justify your answer.

A proton and an α-particle are accelerated through the same potential difference. Which one of the two has less kinetic energy? Justify your answer.

State two important properties of photon which are used to write Einstein’s photoelectric equation.

Define (i) stopping potential and (ii) threshold frequency, using Einstein’s equation and drawing necessary plot between relevant quantities.

Light of intensity ‘I’ and frequency ‘v’ is incident on a photosensitive surface and causes photoelectric emission. What will be the effect on anode current when (i) the intensity of light is gradually increased. In each case, all other factors remain the same. Explain, giving justification in each case.

Light of intensity ‘I’ and frequency ‘v’ is incident on a photosensitive surface and causes photoelectric emission. What will be the effect on anode current when (ii) the frequency of incident radiation is increased. In each case, all other factors remain the same. Explain, giving justification in each case.

Light of intensity ‘I’ and frequency ‘v’ is incident on a photosensitive surface and causes photoelectric emission. What will be the effect on anode current when the anode potential is increased? In each case, all other factors remain the same. Explain, giving justification in each case.

A proton and a deuteron are accelerated through the same accelerating potential. Which one of the two has the greater value of de-Broglie wavelength associated with it, and Give reasons to justify your answer.