HOTs Wave Optics Class 12 Physics

Please refer to Wave Optics HOTs Class 12 Physics provided below with Wave Optics. All HOTs for Class 12 Physics with answers provided below have been designed as per the latest syllabus and examination petter issued by CBSE, NCERT, KVS. Students of Standard 12 Physics should learn the solved HOTS for Class 12 Physics provided below to gain better marks in examinations.

Wave Optics Class 12 Physics HOTs

Assertion (A) & Reason(R)

Question. Assertion : No interference pattern is detected when two coherent sources are infinitely close to each other.
Reason : The fringe width is inversely proportional to the distance between the two slits. Correct

Question. Assertion : When a light wave travels from a rarer to a denser medium, it loses speed. The reduction in speed imply a reduction in energy carried by the light wave.
Reason : The energy of a wave is proportional to velocity of wave. Correct

Question. Assertion: In Young’s experiment, the fringe width for dark fringes is different from that for white fringes.
Reason : In Young’s double slit experiment the fringes are performed with a source of white light, then only black and bright fringes are observed.

Question. Assertion : For best contrast between maxima and minima in the interference pattern of Young’s double slit experiment, the intensity of light emerging out of the two slits should be equal.
Reason : The intensity of interference pattern is proportional to square of amplitude. Correct

Question. Assertion : Interference pattern is made by using blue light instead of red light, the fringes becomes narrower.
Reason : In Young’s double slit experiment, fringe width is given by relation β = λD/d. Correct

Question. Assertion : When a tiny circular obstacle is placed in the path of light from some distance, a bright spot is seen at the centre of shadow of the obstacle.
Reason : Destructive interference occurs at the centre of the shadow. Correct

Question. Assertion : In Young’s double slit experiment if wavelength of incident monochromatic light is just doubled, number of bright fringe on the screen will increase.
Reason : Maximum number of bright fringe on the screen is directly proportional to the wavelength of light used.

Question. Assertion: Diffraction is common in sound but not common in light waves.
Reason : Wavelength of light is more than the wavelength of sound.

Question. Assertion : If complete YDSE (Young’s Double Slit Experiment) is dipped in the liquid from the air, then fringe width decreases.
Reason : Wavelength of light decreases, when we move from air to liquid.

Question. Assertion : In interference and diffraction, light energy is redistributed.
Reason :There is no gain or loss of energy, which is consistent with the principle of conservation of energy.

Case Based Questions

Question. Refraction of a plane wave

Question. What is the angle made by the ray of light on the wavefront?
a) 90˚
b) 0˚
c) 45˚
d) None of the above

Question. Which parameter remains unchanged while a ray of light propagates from one medium to another?
a) velocity
b) Wave length
c) frequency
d) None of the above

Question. According to the above given fig., identify the correct expression for Snell’s law.
a) n1 sin i = n2 sin r
b) n2 sin i = n1 sin r
c) n21 = sin r/ sin i
d) None of the above

Question. When a ray of light travels from a denser to a rarer medium, it
a) it bends towards the normal
b) it travels in a straight line irrespective of angle of incidence.
c) it bends away from the normal
d) None of the above

2) Interference (Young’s Double slit experiment)

Question. what is the phase diff. between two interfering waves producing 1st dark fringe.
a) π
b) 2π
c) 3π
d) 4π

Question. The ratio of the widths of two slits in Young’s double slit experiment is 4 : 1. Evaluate the ratio of intensities at maxima and minima in the interference pattern.
a) 1:1
b) 1:4
c) 3:1
d) 9:1

Question. In a Young’s double slit experiment, the separation between the slits is 0.1 mm, the wavelength of light used is 600 nm and the interference pattern is observed on a screen 1m away. Find the separation between bright fringes.
(a) 6.6 mm
(b) 6.0 mm
(c) 6 m
(d) 60cm

3) Diffraction at a single slit

Question. In the phenomena of Diffraction of light when the violet light is used in the experiment is used instead of red light then,
(a) Fringe width increases
(b) No change in fridge width
(c) Fringe width decreases
(d) Colour pattern is formed

Question. Diffraction aspect is easier to notice in case of the sound waves then in case of the light waves because sound waves
(a) Have longer wavelength
(b) Shorter wavelength
(c) Longitudinal wave
(d) Transverse waves

Question. Diffraction effects show that light does not travel in straight lines. Under what condition the concepts of ray optics are valid. ( D = distance of screen from the slit).
(a) D < Zf
(b) D = Zf
(c) D > Zf
(d) D << Zf