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(Q.25) An object is 7
cm high. The height o its image formed by a plane mirror is
(A) 3.5 cm (B) 7 cm (C) 14 cm (D) 10 cm |
(1Mark)
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(Q.26) State the laws
of reflection.
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(2Marks)
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(Q.27) Why infinite
images are not seen when two plane mirrors are kept facing each other? Give
two reasons.
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(2Marks)
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(Q.28) What do you understand
by the terms inversion and lateral inversion?
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(2Marks)
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(Q.29) Distinguish
between Real image and virtue image.
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(2Marks)
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(Q.30) What should be
the minimum size of a plane mirror, so that a person 160 cm tall can see
himself completely?
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(2Marks)
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(Q.31) State four uses
of a plane mirror.
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(2Marks)
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(Q.32)
Define the following by drawing a
neat diagram:
(i) Mirror (ii) Incident ray (iii)
Reflected ray (iv) Angle of incidence (v) Angle of reflection (vi) Normal to
the point of incidence
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(3Marks)
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(Q.33)
A ray of
light strikes a plane mirror, such that angle with the mirror is 45o
then,
(i) What is the value of angle of reflection? (ii) What is the angle between the incident ray and the reflected ray? |
(3Marks)
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(Q.34) By giving one
example and one use, define regular reflection and irregular reflection.
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(3Marks)
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(Q.35)
Calculate the number of images
formed in two plane mirrors, when they are held at the angle of
(i) 60o� (ii) 40o.
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(3Marks)
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(Q.36) Find the focal
length of a plane mirror with the help of mirror formula.
Explain the power of a plane mirror.
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(3Marks)
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(Q.37) Draw a neat and
clean two ray diagram for the formation of images in two plane mirrors, when
mirrors are (i) at right angles to each other (ii) when mirrors are facing
each other.
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(5Marks)
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(Q.38) Define
reflecting periscope and working of it with the help of a neat and clear
diagram of it. State two advantages and two disadvantages of the reflecting
type periscope.
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(5Marks)
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(Q.10) (a)What
are bad conductors?
(b)Name any two solids which are bad conductor of heat. |
(2Marks)
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(Q.11) Why are non-
metals and organic substances poor conductors?
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(2Marks)
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(Q.1) What is
convection?
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(1Mark)
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(Q.2) Name the process
through which heat is transferred in fluids?
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(1Mark)
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(Q.3) Why heat cannot
be transferred in solids through convection?
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(1Mark)
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(Q.10) Define land
breeze and sea breeze.
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(2Marks)
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(Q.1) Define law of
conservation of energy.
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(1Mark)
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(Q.3) Explain the type
of energy transformation that takes place when we rub our hands.
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(1Mark)
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(Q.4) Name some
renewable and non renewable sources of energy.
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(1Mark)
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(Q.16) Give the
difference between Renewable Sources of energy and non-renewable sources of
energy.
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(Q.1) Name the
instrument used for measuring temperature.
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(1Mark)
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(Q.2) Define
temperature on the basis of kinetic theory of matter.
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(1Mark)
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(Q.3) Give two
characteristics of the Kelvin scale.
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(1Mark)
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(Q.4) What are the
minimum and maximum temperatures measurable by the clinical thermometer and
what does it mean? State the normal temperature of a human body.
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(1Mark)
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(Q.5) Name the two
liquids which are commonly used as thermometric liquids.
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(1Mark)
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(Q.6) What is the
relation between Celsius and Fahrenheit scales?
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(1Mark)
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(Q.7)
(a) What is temperature?
(b) How is heat related to the temperature? Justify your
answer with an example.
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(Q.10) Give two reasons
for using mercury as thermometric liquid.
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(2Marks)
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(Q.11) Define standard
points. Explain the upper standard point and lower standard point.
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(2Marks)
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(Q.12) Give two
disadvantages of the mercury thermometer.
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(2Marks)
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(Q.13) Give the
reference temperatures corresponding to the upper and lower fixed points on
the Celsius, Fahrenheit and Kelvin scale of temperatures.
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(2Marks)
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(Q.4) What is sound?
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(1Mark)
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(Q.5) State a
difference between infrasonic and ultrasonic vibrations.
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(1Mark)
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(Q.6) Define wave.
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(1Mark)
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(Q.7) What is the
relation between frequency and wavelength?
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(1Mark)
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(Q.8) Define time
period of a wave. Give its SI unit.
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(1Mark)
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(Q.9) Define wave
velocity. Give its SI unit.
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(1Mark)
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(Q.164) Define speed of
sound. Name the factors on which the speed of sound depends. Why the
intensity of sound of a speaker is larger immediately after rain?
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(3Marks)
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(Q.165) Are the
particles of the medium dragged along with the wave as sound wave propagates
through the medium? In which medium—solid, liquid or gas, does the sound wave
travel fastest?
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(3Marks)
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(Q.166) Explain, how
compressions and rarefactions are produced in air near a source of sound.
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(3Marks)
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(Q.167) How do sound
waves propagate?
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(3Marks)
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(Q.160) �Find the distance travelled by a
sound wave of frequency 20 KHz, wavelength 1.7 cm in 10 s.�
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(Q.138) What is a crest
and a trough in a wave?
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(1Mark)
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(Q.139) Can
sound wave travel through vacuum?
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(1Mark)
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(Q.140)
The frequency of the tuning fork is 450 Hz. Calculate the
distance travelled by sound when the fork makes 50 vibrations. Take the speed
of sound in air = 320 ms-1.
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(2Marks)
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(Q.141)
When vibration is a necessary condition for a production
of sound, then why the vibrating pendulum does not produce sound?
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(2Marks)
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Question 11
(a)
List two differences between real and virtual images.
(b)
State two characteristics of image formed by a convex mirror.
(c)
With the help of a diagram, define (i) pole, (ii) focal length of a concave
mirror.
(d)
Where should an object be placed in front of a concave mirror to obtain an
image, which is real, inverted and reduced in size?
Question 19
Give
three differences between a concave and convex lens?
