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In This Post we are  providing Chapter-11 Dual Nature of Radiation and Matter NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON DUAL NATURE OF RADIATION AND MATTER

Question 1: A strong argument for the particle nature of cathode rays is that they

(a) produce fluorescence
(b) travel through vacuum
(c) get deflected by electric and magnetic fields
(d) cast shadow

Answer=C

Question 2 : In an electron gun the control grid is given a negative potential relative to cathode in order to

(a) decelerate electrons
(b) repel electrons and thus to control the number of electrons passing through it
(c) to select electrons of same velocity and to converge them along the axis.
(d) to decrease the kinetic energy of electrons

Answer=B

Question 3: When the speed of electrons increase, then the value of its specific charge

(a) increases
(b) decreases
(c) remains unchanged
(d) increases up to some velocity

Answer=B

Question 4: Photoelectric effect is the phenomenon in which

(a) photons come out of a metal when it is hit by a beam of electrons.
(b) photons come out of the nucleus of an atom under the action of an electric field.
(c) electrons come out of a metal with a constant velocity
(d) which depends on the frequency and intensity of incident light wave.

Answer=D

Question 5 : The photoelectrons emitted from a metal surface are such that their velocity

(a) is zero for all
(b) is same for all
(c) lies between zero and infinity
(d) lies between zero and a finite maximum

Answer=D

Question 6 : Photoelectric emission occurs only when the incident light has more than a certain minimum

(a) power   

(b) wavelength
(c) intensity

(d) frequency

Answer=D

Question 7: When light is incident on a metal surface the maximum kinetic energy of emitted electrons

(a) vary with intensity of light
(b) vary with frequency of light
(c) vary with speed of light
(d) vary irregularly

Answer=B

Question 8: A photoelectric cell is a device which

(a) converts light into electricity
(b) converts electricity into light
(c) stores light
(d) stores electricity

Answer=A

Question 9 : The maximum energy of electrons released in a photocell is independent of

(a) the frequency of the incident light
(b) the intensity of the incident light
(c) the nature of the cathode
(d) All of the above

Question 10: The work functions of Silver and Sodium are 4.6 and 2.3 eV, respectively. The ratio of the slope of the stopping potential versus frequency plot for Silver to that of Sodium is

(a) 1

(b) 2

(c) 4

(d) zero

Answer=A

Question 11: In a photoelectric experiment the stopping potential for the incident light of wavelength 4000Å is 2 volt. If the wavelength be changed to 3000 Å, the stopping potential will be

(a) 2 V

(b) zero
(c) less than 2 V

(d) more than 2 V

Answer=D

Question 12: A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed 2 m away, the number of electrons emitted by photocathode are reduced by a factor of

(a) 1/8

(b) 1/16

(c) 1/2

(d) 1/4

Answer=D

Question 13: Light from a hydrogen discharge tube is incident on the cathode of a photoelectric cell, the work function of the cathode surface is 4.2 eV. In order to reduce the photocurrent to zero the voltage of the anode relative to the cathode must be made

(a) – 4.2 V

(b) – 9.4 V

(c) – 17.8 V

(d) + 9.4 V

Answer=B

Question 14: In Davison-Germier experiment, an electron beam is incident on a crystal. The reflected beam consists of

(a) photons

(b) protons
(c) x-rays

(d) electrons

Answer=D

Question 15: In the Davisson and Germier experiment, the velocity of electrons emitted from the electron gun can be increased by

(a) increasing the potential difference between the anode and filament
(b) increasing the filament current
(c) decreasing the filament current
(d) decreasing the potential difference between the anode and filament

Answer=A

In This Post we are  providing Chapter-10 Wave Optics NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

_{NCERT MCQ ON WAVE OPTICS}

Question 1.
What happens if one of the slits, say S₁ in Young’s double , slit experiment-is covered with a glass plate which absorbs half the intensity of light from it?
(a) The bright fringes become less-bright and the dark fringes have a finite light intensity
(b) The bright fringes become brighter and the dark fringes become darker
(c) The fringe width decreases
(d) No fringes will be observed

Answer: (a) The bright fringes become less-bright and the dark fringes have a finite light intensity

Question 2.
What happens to the interference pattern the two slits S₁ and S₂ in Young’s double experiment are illuminated by two independent but identical sources?
(a) The intensity of the bright fringes doubled
(b) The intensity of the bright fringes becomes four times
(c) Two sets of interference fringes overlap
(d) No interference pattern is observed

Answer: (d) No interference pattern is observed

Question 3.
What is the reason for your answer to the above question?
(a) The two sources do not emit light of the same wavelength
(b) The two sources emit waves which travel with different speeds
(c) The two sources emit light waves of different amplitudes
(d) There is not constant phase difference between the waves emitted by the two sources

Answer: (d) There is not constant phase difference between the waves emitted by the two sources

Question 4.
A single slit diffraction pattern is obtained using a beam of red light What happened the red light is replaced by the blue light?
(a) There is no change in diffraction pattern
(b) Diffraction fringes become narrower and crowded
(d) Diffraction fringes become broader and farther apart
(d) The diffraction pattern disappear

Answer: (b) Diffraction fringes become narrower and crowded

Question 5.
When a polaroid is rotated, the intensity of light varies but never reduces to zero. It shows that the incident light is:
(a) unpolarized
(b) completely plane polarized
(c) partially plane polarized
(d) None of the above

Answer: (c) partially plane polarized

Question 6.
When a polaroid is rotated, the intensity of light does not vary. The incident light may be:
(a) unpolarized
(b) completely polarized
(c) partially plane polarized
(d) None of the above

Answer: (a) unpolarized

Question 7.
In Young’s double slit experiment, a maximum is obtained when the path difference between the interfering waves is (n ∈ l):
(a) nλ
(b) n λ2
(c) (2n + 1) λ2
(d) (2n – 1) λ4

Answer: (a) nλ

Question 8.
For sustained interference, we need two sources which
emit radiations :
(a) of the same intensity
(b) of the same amplitude
(c) having a constant phase difference
(d) None of these

Answer: (c) having a constant phase difference

Question 9.
Two sources of light are said to be coherent when both give out light waves of the same:
(a) amplitude and phase
(b) intensity and wavelength
(c) speed
(d) wavelength and a constant phase difference

Answer: (d) wavelength and a constant phase difference

Question 10.
The intensity of light emerging from the two slits, in Young’s experiment is in the ratio 1 : 4. The ratio of, the intensity of the minimum to that of the consecutive maximum will be:
(a) 1 : 4
(b) 1 : 9
(c) 1 : 16
(d) 2 : 3

Answer: (b) 1 : 9

Question 11.
Poisson’s bright spot was discovered by:
(a) Fresnel
(b) Rayleigh
(c) Poisson
(d) Fraunhoffer

Answer: (c) Poisson

Question 12.
The theory of expanding universe is confirmed by the observation of the spectral lines of the star, which shows :
(a) green shift
(b) red shift
(c) violet shift
(d) yellow shift

Answer: (b) red shift

Question 13.
The application of Doppler effect are:
(a) Doppler spectrometer
(b) Doppler radius
(c) Doppler velocimeter
(d) All of these

Answer: (d) All of these

Question 14.
Which of the following is conserved when light waves interfere?
(a) phase
(b) intensity
(c) amplitude
(d) none of these

Answer: (d) none of these

Question 15.
In Young double slit experiment, a minimum is obtained when the phase difference of the superposing waves, is (n ∈ l):
(a) nπ
(b) (n + 12)π
(c) (2n + 1)π
(d) zero

Answer: (c) (2n + 1)π

In This Post we are  providing Chapter-9 Ray Optics and Optical Instrument NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON RAY OPTICS AND OPTICAL INSTRUMENT

Question 1.
A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first color to emerge is
(a) blue.
(b) green.
(c) violet.
(d) red.

Answer: (d) red.

Question 2.
You are given four sources of light each one providing a light of a single color – red, blue, green and yellow. Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incidence at the interface of two media is 90°. Which of the following statements is correct if the source of yellow light is replaced with that of other lights without changing the angle of incidence?
(a) The beam of red light would undergo total internal reflection.
(b) The beam of red light would bend towards normal while it gets refracted through the second medium.
(c) The beam of blue light would undergo total internal reflection.
(d) The beam of green light would bend away from the normal as it gets refracted through the second medium.

Answer: (c) The beam of blue light would undergo total internal reflection.

Question 3.
The optical density of turpentine is higher than that of water while its mass density is lower. Figure shows a layer of turpentine floating over water in a container. For which one of the four rays incident on turpentine in figure, the path shown is correct?

(a) 1.
(b) 2
(c) 3
(d) 4

Answer: (b) 2

Question 4.
There are certain material developed in laboratories which have a negative refractive index (figure). A ray incident from air (medium 1) into such a medium (medium 2) shall follow a path given by

Answer: (a)

Question 5.
Consider an extended object immersed in water contained in a plane trough. When seen from close to the edge of the trough the object will not look distorted because
(a) the apparent depth of the points close to the edge are nearer the surface of the water compared to the points away from the edge.
(b) the angle subtended by the image of the object at the eye is smaller than the actual angle subtended by the object in air.
(c) some of the points of the object far away from the edge may not be visible because of total internal reflection.
(d) water in a trough acts as a lens and magnifies the object.

Answer: (d) water in a trough acts as a lens and magnifies the object.

Question 6.
A rectangular block of glass ABCD has a refractive index 1.6. A pin is placed midway on the face AB (figure). When observed from the face AD, the pin shall

(a) appear to be near A.
(b) appear to be near D.
(c) appear to be at the center of AD.
(d) not be seen at all.

Answer: (d) not be seen at all.

Question 7.
An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Which one of the following is not possible?
(a) The length of the telescope tube is 20.02 m.
(b) The magnification is 1000.
(c) The image formed is inverted.
(d) An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image.

Answer: (d) An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image.

Question 8.
An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror, the displacement of the image will be:
(a) 30 cm away from the mirror
(b) 36 cm away from the mirror
(c) 30 cm towards the mirror
(d) 36 cm towards the mirror

Answer: (b) 36 cm away from the mirror

Question 9.
The refractive index of the material of a prism is √2 and the angle of the prism is 30°. One of the two refracting surfaces of the prism is made a mirror inwards, by silver coating. A beam of monochromatic light entering the prism from the other face will retrace its path (after reflection from the silvered surface) if its angle of incidence on the prism is:
(a) 60°
(b) 45°
(c) 30°
(d) zero

Answer: (b) 45°

Question 10.
A diverging lens with magnitude of focal length 25 cm is placed at a distance of 15 cm from a converging lens of magnitude of focal length 20 cm. A beam of parallel light falls on the diverging lens. The final image formed is:
(a) real and at a distance of 40 cm from the divergent lens
(b) real and at a distance of 6 cm from the convergent lens
(c) real and at a distance of 40 cm from convergent lens
(d) virtual and at a distance of 40 cm from convergent lens.

Answer: (c) real and at a distance of 40 cm from convergent lens

Question 11.
The bouncing back of light when it strikes a smooth or polished surface is called …………….. of light.

(a) Refraction
(b) Reflection
(c) Dispersion
(d) Divergence

Answer: (b) Reflection

Question 12.
When light is reflected from a polit, surface the angle of incidence is …………… to the angle of reflection.

(a) Equal
(b) Same
(c) Different
(d) zero

Answer: (a) Equal

Question 13.
The image formed by a plane mirror shows …………….. inversion.

(a) Incident
(b) Parallel
(c) Transverse
(d) Lateral

Answer: (d) Lateral

Question 14.
A plane drawn perpendicular to the principal axis and passing through the principal focus is called ………………. plane.

(a) Focal
(b) Principal focus
(c) Optical center
(d) Optical axis

Answer: (a) Focal

Question 15.
The size of the mirror is called its …………………..

(a) Axis
(b) Focal
(c) Principal axis
(d) Aperture

Answer: (d) Aperture

In This Post we are  providing Chapter-8 Electromagnetic Waves NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON ELECTROMAGNETIC WAVES

Question 1.
The dimensional formula of E⃗  is:
(a)[MLT^-2A^-1]
(b) [MLT^-3A^-1]
(c) [MLT^-2A^-2]
(d) None of these

Answer: (b) [MLT^-3A^-1]

Question 2.
The dimensional formula of is:
(a) [MLT^-2A^-1]
(b) [ML⁰T^-2A^-1]
(c) [ML⁰T^-3A^-1]
(d) None of these

Answer: (b) [ML⁰T^-2A^-1]

Question 3.
Which of the following has the dimensions of current?
(a) ε₀ E⃗ .dt→
(b) µ₀ E⃗ .dt→
(c) B⃗ .dl→µ0
(d) B⃗ .dl→ε0

Answer: (c) B⃗ .dl→µ0

Question 4.
Which of the following has the dimensions of charge?
(a) ε0E⃗ ds→
(b) µ₀ E⃗ .ds→
(c) ε0µ0 E⃗ .ds→
(d) µ0ε0 E⃗ .ds→

Answer: (a) ε0E⃗ ds→

Question 5.
Maxwell’s equation involving ddt B⃗  is obtained-from:
(a) Ampere’s law
(b) Gauss’s law
(c) Faraday’s law
(d) Biot-Savart’s law

Answer: (c) Faraday’s law

Question 6.
The dimensions of E⃗ , dl→ are identical to that of:
(a) potential
(b) charge
(c) current
(d) None of these

Answer: (a) potential

Question 7.
Which of the following laws was modified by Maxwell by introducing the displacement current?
(a) Gauss’s law
(b) Ampere’s law
(c) Biot-Savart’s law
(d).None of these

Answer: (b) Ampere’s law

Question 8.
Choose the wave relevant to telecommunication :
(a) ultraviolet
(b) infrared
(c) microwave
(d) visible light

Answer: (c) microwave

Question 9.
Electromagnetic waves have a speed of
(a) 3 × 10⁵ kms^-1
(b)3 × 10⁶ kms^-1
(c) 3 × 10⁷ kms^-1
(d) 3 × 10⁸ kms^-1

Answer: (a) 3 × 10⁵ kms^-1

Question 10.
Which of the following EMW has highest wavelength?
(a) X-ray
(b) ultraviolet rays
(c) infrared rays
(d) microwaves

Answer: (c) infrared rays

Question 11.
Displacement current is due to:
(a) the flow of electrons
(b) the Varying electric field
(c) the ionization of atmosphere
(d) the flow of protons

Answer: (b) the Varying electric field

Question 12.
Displacement current is always :
(a) equal to conduction current
(b) less than conduction current
(c) greater than conduction current
(d) the sum of current due to flow of positive and negative ions

Answer: (a) equal to conduction current

Question 13.
EMW are produced by:
(a) charge in uniform motion only
(b) charge at rest only
(c) accelerated or decelerated charge only
(d) all of the above

Answer: (c) accelerated or decelerated charge only

Question 14.
Who first demonstrated the existence of em waves?
(a) Hertz
(b) Maxwell
(c) Ampere
(d) Faraday

Answer: (a) Hertz

Question 15.
If B⃗  is the magnetic field vector and E⃗  is the electric field vector in an em wave, then which of the following relations is correct? Here c is the speed of fight:
(a) c = EB
(b) c = BE
(c) c = BE
(d) c = 1EB

Answer: (a) c = EB

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