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IX science Mix SS2 crash 2011 Section A
1) What is the audible range of the average human ear?
2) What is buoyancy?
3) The electronic configuration of an element is 2,8,8. What is its atomic number and name of the element?
4) If a body falls from a height, how will its P.E. change?
5) Give an example of a diatomic and triatomic gas.
6) Out of cotton and iron, each having mass 100 Kg. one is heavier. Which is heavier and why?
7) If the velocity of sound in a medium is 1500 m/s and wavelength is 90 m. Will the sound be heard by a normal person?
8) Write the valency of (a)Hydrogen in CH4 (b)Phosphorus in P2O5 (c) Phosphorus in PH3 (d)Aluminium in Al2 (SO4)3
9) Why chlorine atom becomes Cl - , when it gains one electron?
10) A lamp consumes 1000J of electrical energy in 20 seconds. What is its power?
11) Audible range for normal human ear is 20 Hz. to 20,000 Hz. What are the wavelengths of sound wave in air corresponding to these two frequencies? Take speed of sound as 340 m/s.
12) Describe Bohr’s model of the atom?a. How many grams of chlorine are contained in one mole of chlorine? b. Calculate the mass of one molecule of chlorine.
13) Can a body have energy without having momentum or Can a body have momentum without having energy? Explain.
14) Explain how mechanical energy is conserved during the oscillations of a simple pendulum.b. A crane is used to lift 500 Kg mass of two blocks up to 10m. It takes 2 minutes for first block and 5 minutes for second block .In which case is amount of work done will be more and in which case power is more. ( g= 10 m /s2 )
15) On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole?
16) The speed of sound in air is: (a)Less than in solids and liquids (b) Same as that in solids and liquids (c) Greater than that in solids and liquids (d) None of these
17) A pulse is formed:(a)In a small part of the medium. (b)In a vacuum. (c)In a large part of the medium(d) All of the above
18) When a solid is immersed partly or wholly in a fluid then it experiences:
(a)An apparent gain in weight(b)An apparent loss in weight (c)No change in weight(d)None of these
19) If atomic no. of element X is 17 and mass no. = 37, then no. of protons is (a)17 (b)34 (c)20 (d)37
20) If K and L energy shells of an atom are full then total no. of electrons in the atom are:(a)8 (b)18 (c)10 (d)28
21) The mass of 0.2 mol atom of oxygen is (a)16g (b)8g (c)32g (d)3.2g
22) The formula of compound formed by Hg 2+ and O 2- is: (a)Hg O (b)Hg2 O2 (c)Hg2 O (d)Hg O2
23) S.I. unit of Energy is:(a)Newton (b)erg (c)Joule (d)dyne
24) In case of freely falling body, Kinetic energy is maximum at -(a)Maximum height (b)mid way (c)just before touching the ground (d)at ground
25) How many atoms are present in-(a) H2S molecule (b)PO43- ion
26) According to Dalton’s atomic theory, what is the definition of atoms?
27) Calculate the molar mass of Nitric Acid HNO3 (atomic mass of H=1, N=14, 0=16)
28) Calculate the no of moles for 53g of He.
29) How many molecules are present in 34 g of ammonia?
30) When ice melts, there is decrease in volume instead of increase. Why?
31) Calculate % composition of Sulphur element in H2SO4.
32) Which has more no. of atoms - 100 g of sodium or 100 g of iron.(Na = 23u , Fe = 56u)
33) Names of the elements present in the following compounds(a)Baking Powder (b)Quick Lime
34) If one mole of oxygen atom weighs 16g, what is the mass in g of 1 atom of oxygen?
35) Convert into mole:(a)22 g of CO2 9b)12 g of oxygen gas
36) Calculate the number of molecules of Sulphur (S8) present in 16 g of solid sulphur.
37) Calculate the number of aluminum ions present in 0.051g of aluminum oxide.
38) State the law of conservation of mass? What mass of silver Nitrate will react with 5.85g of sodium chloride to produce 14.35 g of silver chloride and 8.5 g of sodium Nitrate if law of conservation of mass is true?
39) What is Dalton’s Atomic theory? Give its advantages and drawbacks.
40) Define mole. Give its symbol. Also define molar mass.
41) What is the work done when a body is moved horizontally along a frictionless surface?
42) Define 1 Joule. What is the work done on a body moving in a circular path?
43) When is work said to be done against the force of gravity?
44) Define 1 watt. What is kinetic energy?What will happen to the Kinetic Energy of a body if its velocity is doubled?
45) Name four units of energy. In a tug of war, one team gives way to other. What work is being done and by whom?
46) . Name the transformation of energy involved in these cases-(a)Electric Heater (b)Dynamo (c) Microphone (d)Electric Cell (e)Headphone (f)Photoelectric Cell(g)When Coal burns
47) A person holds a body of mass 20 kg over his head for 10 sec. Has he done any work? Justify your answer.
48) A free falling body stops on reaching the ground. What happens to its kinetic energy?
49) How are K.E. and momentum related? Is it possible that a body be in accelerated motion under a force and no work is being done by the force?
50) When an arrow is shot from its bow, it has K.E. From where does it get the K.E.?
51) A force acting on a 20 kg mass changes its velocity from 5m/s to 2 m/s. Calculate the work done.
52) The K.E. of an object of mass m moving with a velocity of 5m/s is 25 J. What will be its K.E. when its velocity is doubled? What will be its K.E when its velocity is increased 3 times?
53) An object of mass 12 Kg is at a certain height above the ground. If the gravitational P.E. is 480 J, find the height at which the object is w.r.t the ground (g= 10m/s 2)
54) An object of mass 40 kg is raised to a height 5 m above the ground. What is its P.E.? If object is allowed to fall, find its K.E. just before touching the ground and also its K.E. when it is half way down.
55) What is the work done to increase the velocity of car from 36 km/h to 72km/h , if the mass = 1500Kg.
56) A man whose mass is 50 kg climbs up 30 steps of a stair in 30 s. If each step is 20 cm high, calculate the power used in climbing stairs.
57) Deduce a formula for K.E of a body.
58) State the law of conservations of energy. Show that when a body falls from a height the total mechanical energy remains same.
59) P.E. of a person is maximum when he is -(a)standing (b)sitting on a chair(c)sitting on the ground(d)lying down on the ground
60) Work done by moon in moving around earth-(a) +ve (b)-ve (c)zero(d)unknown
61) Work is measured as product of-(a)Force and time(b)Force and displacement (c)Power and displacement (d)Force and acceleration
62) Value of g is -(a)9.8 m/s(b)9.8 cm/s2 (c)9.8 m/s2 (d)9.8 cm/s
63) If mass if the body is doubled, Kinetic energy will be -(a)same(b)halved(c)doubled(d) four times
64) Which sound has a higher pitch, guitar or car horn?
65) Name three animals which can hear ultrasonic vibrations.
66) How are the wavelength and frequency of a sound related to its speed?
67) What is a wave? Why sound wave is called a longitudinal wave?
68) Frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?
69) What is an echo?.What do waves transport - matter or energy?
70) Which characteristics of the sound help us to identify a person by his voice if he is sitting in a dark room?
71) If the amplitude of a wave is doubled, what will be the effect on its loudness?
72) Which wave property determines a) loudness, b) Pitch?
73) Why are the ceilings of concert halls curved?
74) Why sound waves are called mechanical waves? How is ultrasound used for cleaning?
75) Sound is produced due to a vibratory motion, then why a vibrating pendulum does not produce sound?
76) A sound produces 20 crests and 20 troughs in 0.4 sec. Find the frequency of the wave.
77) How is sound produced in school bell?
78) Bats have no eyes then how do they catch their prey?
79) What is SONAR?
80) Write three uses of multiple reflection of sound.
81)
Calculate the wavelength of a sound whose
frequency is 220 Hz and speed is 440 
in a given medium.
82) A body is vibrating 6000 times is 1 minute. If the velocity of sound in air is 360 m/s, find Frequency in Hz wavelength of sound.
83) A stone is dropped from a 500 m tall building into a pond. When is sound splash heard? Given g=10 m/s2 , speed of sound = 340 m/s.
84) An echo is heard in 3 sec after the emission of sound. If speed of sound in air is 342 m/s, what is the distance of the reflecting surface from the source?
85) For reflection of sound wave, we need -(a)A polished mirror(b)A large size, opaque reflecting surface(c)A concave surface(d)A glass plate
86) The speed of sound in air is -(a) Less than in solids & liquids(b)Same as that in solids & liquids(c)Greater than in solids and liquids(d)None of these
87) We can sense a compression in a spring if-(a)Turns are close together(b)Neither closes nor apart(c)Turns are further apart than normal(d)None of these
88) When sound is allowed to fall normally on the reflecting surface, the angle at which the intensity of sound will be maximum is:(a)600(b)900(c)300(d)00
89) The mechanical wave is(a)Sound Wave(b)Microwave(c)Radio Wave(d)Light Wave(c)
90) Sound wave cannot pass through (a)Metals(b)Water (c)Air (d)Vacuum
91) The persistence of sound is an auditorium is the results of(a)Single reflection of sound (b) Repeated reflection of sound (c)Repeated refraction of sound (d) Vibration of object placed in an auditorium
92) A wave set up a single disturbance of short duration is called-(a) pulse (b)Sound Wave (c)A Wave (d)None of these
93)
To determine the velocity of a pulse
propagated through a stretched slinky (a) A slight jerk is given to the slinky
(b)No jerk is given to the slinky (c)Sharp jerk is given to the slinky (d)None
of these.
94) The distance x in below diagram is-(a)l (b)2l(c)3l/2 (d)l/2
95) Two sounds of same pitch and loudness differ in (a)Tone(b)Note (c)Quality (d)All of these
96) Why do camels have broad feet?
97) State the law of floatation?
98) Define relative density. What is its SI unit?
99) What is the unit of gravitational constant G?
100) Define acceleration due to gravity?. Convert 1 kg.wt into Newtons.
101) A body of mass 50g floats in water. What will be its apparent weight? Explain your answer.
102) Will a body weigh more in air or in vacuum when weighed with a spring balance? Explain your answer.
103) A stone is dropped freely in the river from a bridge. The stone take 2 seconds to touch the water surface. Calculate the height of the bridge from the water level. (g= 9.8m/s2).
104) Explain why a gas bubble released at the bottom of a lake grows in size as it rises to the surface of the lake?
105) A piece of ice floating in a glass of water melts but level of water in glass does not change. Explain.
106) An iron ball of density 7800kg/m3 and volume 200 cm3 is totally immersed in water ( take g=10 m/s2) (a)Calculate the weight of iron ball in air. (b) Calculate the upthrust.(c)Its apparent weight in water.(d)Its apparent density in water.
107) Apparent loss of weight of solid in water is equal to (a)Weight of water left in the overflow vessel.(b)Weight of water displaced by solid.(c)Total weight of water taken in overflow vessel.(d)None of these.
108) Apparent loss in weight of a body when it is fully or partially immersed in water is due to (a)Buoyant force(b)Gravitational force(c)Both(d)None of these
109) .A wooden cylinder floats vertically in water with half of its length immersed. The density of wood is(a)Equal to that of water
(b)half the density of water (c)double the density of water (d)can’t say
110) In television picture tube which type of rays are used?
111) Which is heavier, neutron or proton? Compare them respect to their charge?
112) If electrons move from K to L shell, will the energy be absorbed or evolved?
113)
Give one point of similarity and one
difference between 
and 
.
114) Helium atom has an atomic mass of 4u and two protons in its nucleus. How many neutrons does it have?
115) An ion X 2+ contains 18 electrons and 20 neutrons. Calculate the atomic number and mass no. of element X. Name the element X.
116) In a given electric field, β- particles are deflected more than α- particles inspite of the fact that α - particles have larger charge, why?
117) Give one Achievement and one limitation of J.J Thomson’s model of atom?
118)
If
Bromine atom is in the form of two isotope 
(49.7 %) and 
(50.35%) then find mass of Br atom
119) What are valence electrons? What is their significance?
120) What would be the observation if the α - particle scattering experiment is carried out using a foil of a metal other than gold?
121) Electronic configuration of Potassium is 2,8,8,1 and Calcium 2,8,8,2, when M shell can have maximum of 18 electrons then why next element Scandium has electronic configuration 2,8,9,2 and not 2,8,8,3 ?
122) What are isotopes and Isobars? What are two isotopes of chlorine?Calculate the average atomic mass of a chlorine atom?
123) What is present concept of an atom? Explain in detail? Why this model is considered to be the most appropriate model?
124) Explain the Rutherford’s alpha particle scattering experiment. What were the main conclusions drawn from this experiment?
125) Rutherford’s -particle scattering experiment led to the discovery of:(a)Nucleus (b)Electrons
(c)Protons (d)Neutrons
126) If atomic No. of an element is 3 , then its valency is (a)3(b)2(c)1(d)6
127) The fruit which resembles Thomson’s model of an atom is :(a)Papaya b)Watermelon (c)Apple (d)Orange
128) Out of these, which rays has maximum wavelength(a)Ultraviolet rays(b)Radio waves (c)Infrared rays(d)X-rays
129) Charge on X-rays is (a)Positive(b)Negative (c)No charge (d)Can’t say
130) Draw the labeled diagram of areolar tissue.Mention uses of
131) What are properties of vertebrates?
132) How do poriferans differ from coelenterates ?
133) What are the differences between gymnosperms and angiosperms?
134) Draw a neat and labeled diagram of Euglena (b)Paramecium
135) Which group is called amphibian of plant kingdom? Why? label the diagram of pteridophyte (Marsilea
136) Identify the groups which they belong to and give 2 examples of its members :
137) Sucker in parasites and segmented body
138) Blood does not flow in blood vessels but also in body cavity. It also has ‘joined legs’.
139) It is cold-blooded and it also has two chambered heart.
140) It has lungs in larval stage and can breath through its skin.
141) It has hard exoskeleton and has pores called ostia in its body
142) It shows sexual dimorphism(males differ from female) and some of its members cause disease like elephantiasis.
143) Write the differences in the follow :(i)Poriferans and coelenterates(ii)Annelids and arthropod(iii)Amphibians and reptiles
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