DUAL NATURE OF MATTER
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1 marks question
Which part of electromagnetic spectrum has largest penetrating power? (2010)
A lane electromagnets wave travels in vacuum along Z-direction. What can you say about the
direction of electric and magnetic and magnetic field vectors?
(2011)
Write Einsten‘s photoelectric equation. State clearly how this equation is obtained using the
photon picture of electromagnetic radiation. Write the three salient features observed in
photoelectric effect which can be explained using this equation. (2012)
The carrier wave represented by
C(t)=5 sin ( t) volt
A modulating signal is a square wave as shown.
Determine modulation index.
2 MARKS QUESTION
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Draw the circuit diagram of an illuminated photodiode in reverse bias .How is photodiode used
to measure light intensity?
(2010)
Arrange the following electromagnetic radiations in ascending order of frequencies
(i) Microwave, (ii) Radio wave,(iii) X-rays,(iv)Gamma rays. Write two uses of any one of these.
AN electron is accelerated through a potential difference of 100 volts. What is the de-Broglie
wavelength associated with it. To which art of the electromagnetic spectrum does this value of
wave length correspond?
(2010)
For a single slit of width “a” the first minimum of the interference pattern of a monochromatic
light of wavelength λ occurs at an angle of λ/a. At the same angle of λ/a, we get a maximum for
two narrow slits separated by a distance “a” explain.
(2013)
A proton and alpha particle are accelerated through the same potential .Which one of the two
has
i) greater value of de-Broglie wavelength associated with it and
ii) less kinetic energy. Give reason to justify your answer.
(2013)
Find an expression for intensity of transmitted light when a Polaroid sheet is rotated between
two crossed Polaroid’s. In which position of the Polaroid sheet will the transmitted intensity be
maximum?
(2014)
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3 MARKS QUESTION
Write Einstein’s photoelectric equation. State clearly how this equation is obtained using the
photon picture of electromagnetic radiation.
Write the three salient features observed in photoelectric effect which can be explained using
this equation.
(2012)
(a)Why are coherent sources necessary to produce a sustained interference pattern? (b) In
young’s double slit experiment using monochromatic light of wavelength ‘λ’ the intensity of
light at a point on the screen where path difference is a, is k units. Find out the intensity of light
at a point where path difference is λ /3.
(2012)
4 MARKS QUESTION
10. When Sunita, a class (xii) student, came to know that her parents are planning to rent out the
top floor of their house to a mobile company she protested. She tried hard to convince her
parents that this move would be a health hazard.
(i.)In what way can be the setting up of transmission tower by a mobile company in a residential
colony proves to be injurious to health?
(ii) By objecting to this move of her parents, what value did Sunita display? (iii)Estimate the
range of electromagnets wave which can be transmitted by an antenna of height 20m. (given
values of the earth=6400km).
(2013)
5 MARKS QUESTION
11. Write Einstein’s photo electric equation and mention which important features in photoelectric
effect can be explained with the help of this equation. The maximum kinetic energy of the
photoelectrons gets doubled when the wavelength of light incident on the surface changes
from Y1 t Y 2 .Derive the expression for the threshold wavelength Y0 and work function for the
metal surface.(2014)
12. Name the arts of electromagnetic spectrum which is (a) suitable for radar systems used in
aircraft navigations. (b)used to treat muscular strain. (c) used as a diagnostic tool in medicine.
Write in brief these waves can be produced. (2015)
13. a) In a double slit experiment using light of wavelength 600nm, the angular width of the fringe
fringe formed on a distant screen is 0.1 . Find the spacing between the two slit.
(b)Light of wavelength 5000A0 Propagating in air gets partly reflected from the surface of water
.How will the wave lengths and frequencies of the reflected light be affected?