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Question 1.
i despirately want to join narayana coaching center how can i do so????????? plz help
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Question 2.
(1)In a standing wave,maximum speed of a particle of medium is at antinode.How?
(2)If the two waves are in phase at t=0,they will again be in phase when the first wave has gone through exactly one more cycle than the second.This will happen at time t=T(the period of Beat).Give reason for both statements and explain.
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Question 3.
if accleration due to gravity at 20m from surface of earth is 9m/s^2.
find aac.due to gravity at 40m below from the surface of earth?
also give justification.
Answer: its 9 m/s^2
b/c d=2h
means gravity at d distance below from surface is same as h distance above from surface.
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Question 4.
From where i can get fitt-jee previous papers for class-x?
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Question 5.
if a guard is there,guiding the 4 different ways,he aways says "false" about 4 ways i.e. is the way have difficulty or not?find the statement that if u asks to the guard he always says
"true"
Answer: draw a truth table having 4 statementes e.g. p,q,r,s. by using logical connectives make a statement which is always ture i.e. tuotology.
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Question 6.
can u sent me iit jee question papers to my email id pls?
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Question 7.
For a + integer let f n (A) = tan(A/2)(1+sec A)(1+sec 2A)(1+sec 4A).... (1+sec 2 n A) {raised to the power of n} then
options:
1. f 2 (pi/16) = 1
2. f 3 (pi/32) = 1
3. f 4 (pi/64) = 1
4. f 5 (pi/126) = 1
Answer: answer : 1, 2, 3, 4
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Question 8.
bag-a contains 4 white and 5 red balls,bag-b contains 6 white and 7 red balls.what is the probailty of drawing a red ball at random and that ball drawn is from bag-a
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Question 9.
The locus of the centre of circle which touches (y-1)2+x2=1 externally and also touches x-axis is :
1)x2=4yU(0,y) y<0
2)x2=y
3)y=4x2
3)y2=4xU(0,y), y E R
Answer: (3)
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Question 10.
A scooter is traveling on a straight road with the speed of 30km/hr. Behind the scooter there is a car traveling at a speed of 45km/hr. When the distance between them is 7.5km the car gives an acceleration of 15km/hr^2.After what distance and time will the car catch the scooter?
more questions for IIT JEE is available at http://www.gurukulinfo.com/sample-question-papers-previous-years-questions-papers
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Question 11.
The minimum velocity (in ms-1) with which a car driver must traverse a flat curve of radius 150 m and coefficient of friction 0.6 to avoid skidding is
(a) 60 (b) 30 (c) 15 (d) 25
Answer: 30
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Question 12.
which of the following oxide is neutral?why?
A.CO
B.SnO2
C.ZnO
D.SiO2
Answer: co
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Question 13.
In Pottassium atom, electronic energy level is in the following order.
A.4s > 3d
B.4s < 2p
C.4s < 3d
D.4s > 4p
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Question 14.
Which of thefollowing are amphoteric?why?
A.Be(OH)2
B.Sr(OH)2
C.Ca(OH)2
D.None
Answer: A.Be(OH)2
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Question 15.
What is the value of fundamental imaginary power to that of i, Where i is iota ?
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Question 16.
Give the range of ultrasonic vibration?
A-Less than 20hertz
B-More than 20,000hertz
C-20hertz to 20,000hertz
Answer: Answer= C-20hertz to 20,000hertz
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Question 17.
International Union for Conservation of Nature and Natural Resources(IUCN),is renamed as what?
1-United Nations Enviroment Programme(UNEP).
2-Convention on International Trade in Endangered Species(CITES).
3-World Conservation Union(WCU).
Answer: Answer= 3-World Conservation Union(WCU).
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Question 18.
In how many ways a lock having two ring combination can be opened ,if each ring has numbers from zero to ten?
Answer: Total No of Out comes = 11 x 11 = 121
favourable case = only one no. = 01
Probbility = 1/121
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Question 19.
There are n locks and n keys.Each lock has one unique key.Find the maximum number of trials required to separate out each lock and its unique key.
Answer: since n locks and n keys are used,to seperate these locks and keys with their unique combinations,each key is used n times.Once the correct combination is found for one key,the other key is tried n-1 times.And so the keys and the number of trials are reduced in the form of n!....therefore the correct answer is n! times.
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Question 20.
If a+b+c=0
find if roots of equation 4ax^2+3bx+2c=0 are:-
(a)real and distinct
(b)real and equal
(c)imaginary
show the working
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Question 21.
A passenger who weighs 180 lbs stands on a scale in an elevator. The scales read 190 lbs. The elevator could be
(a) moving upward and increasing its speed
(b) moving upward and decreasing its speed
(c) moving downward and increasing its speed
(d) moving downward at a constant speed
Probably moving upward and increasing in speed since there is a net force on the person greater than their weight.
also explain the questions asked
Answer: it is moving upward and accelerating that is increasing the speed .this is because when elevator is going up acceleration changes to (g+a)therefore 180 lbs is changing to 190 lbs
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Question 22.
A ball is launched from ground level with initial velocity components vox and voy and flies through the air, reaching a maximum height, having a certain time of flight, and reaching a certain range. How will EACH of these 3 quantities change (increase/decrease/unchaged) if we increase vox (but keep voy at its original value)?
Maximum Height-- Time of Flight-- Range
(a) increase increase increase
(b) unchanged unchanged increase
(c) decrease decrease decrease
(d) increase unchanged unchanged
(e) decrease increase unchanged
Changing Vx wouldn only change the range since x/y components are independent, correct?
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Question 23.
A rock is thrown straight up. It reaches the top of its path and starts to fall back down. It’s acceleration on the way down, neglecting air resistance, is:
(a) greater than when it was at the top of its path.
(b) the same as when it was at the top of its path.
(c) less than when it was at the top of its path.
Answer: ans is b
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Question 24.
Find all angles between 0° and 360° which satisfy the following equation:
(sin x - cos x)² = 2
Answer: (sin x - cos x)² = 2
=> sin² x + cos² x - 2sinxcosx = 2
=> 1 - sin 2x = 2
=> sin 2x = -1
=> 2x = 270°
=> x = 135°
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Question 25.
Prove that the lines joining the midpoints of opposite sides of a quadrilateral bisect each other. (a line or segment bisects another segment if it divides the segment into 2 equal parts) Hint: Let the vertices of the quadrilateral be (0,0), (a,b), (c,d), (e,0)
Answer: The vertices are A(0,0), B(a,b), C(c,d) and D(e,0)
Midpoint of AB is (a/2, b/2) and midpoint of CD is [(c+e)/2, d/2]
The midpoint of these two points is [(a+c+e)/4, (b+d)/4]
Midpoint of BC is [(a+c)/2, (b+d)/2] and of AD is (e/2, 0)
The midpoint of these two points is [(a+c+e)/4, (b+d)/4]
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Question 26.
find the sum of
1/(sinA + sin2A) + 1/(sin2A + sin3A) + 1/(sin3A + sin4A)........to n terms
Answer: sin(x) + sin(y) = 2sin((x + y)/2)cos((x - y)/2)
sin(nA) + sin((n + 1)A) =
2sin((2n + 1)A/2)cos(- A/2) =
2sin((2n + 1)A/2)cos(A/2)
n
? 1/[2sin((2k + 1)A/2)cos(A/2)] =
k=1
. . . . . . . . . . . . . . n
{1/[2ncos(A/2)]} ? 1/sin((2k + 1)A/2) =
. . . . . . . . . . . . . k=1
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Question 27.
Let f(x) = ax^2 + bx + c where a, b, c ? IR. Prove that if f(x) is an integer when x is an integer, then 2a, a + b, c are all integers. Conversely, prove that if 2a, a + b, c are all integers then f(x) is an integer whenever x is an integer.
Answer: If f(x) is an integer when x is an integer, then 2a, a + b, and c are integers.
Proof:
(1) 0 ? Z, therefore, f(0) = c ? Z
(2) 1 ? Z, therefore f(1) = a + b + c ? Z ? 2f(1) = 2a + 2b + 2c ? Z (because Z is closed under multiplication)
(3) 2 ? Z, therefore, f(2) = 4a + 2b + c ? Z
Thus subtracting f(2) - 2f(1) we get that:
2a - c ? Z because Z is closed under addition, but we already know that c ? Z. Therefore, 2a ? Z because Z is closed under addition.
Going back to f(1) = a + b + c = (a + b) + c we know that c ? Z, therefore it must be certainly true that a + b ? Z because Z is closed under addition
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Question 28.
for every natural number 'n', prove that:
v(4n + 1) < (vn) + {v(n + 1)} < v(4n + 2)
hence or otherwise, prove that:
[(vn) + {v(n + 1)}] = [v(4n + 1)]
where [x] is the greatest integer not exceeding x.
Answer: For every natural number n,
4n² < 4n² + 4n < 4n² + 4n + 1
=> 2n < 2v[n(n+1)] < 2n + 1 (taking square-roots)
=> 4n + 1 < 2n + 1 + 2v[n(n+1)] < 4n + 2 (adding 2n + 1)
=> v(4n + 1) < vn + v(n + 1) < v(4n + 2) (taking square-roots)
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Question 29.
Solve for x
[(5 + 2v6)^(y)] + [(5 - 2v6)^(y)] = 10
where y = x^2 - 3
Answer: Let 5 + 2v6 = m
=> 5 - 2v6 = 1/m
=> m^y + 1/(m^y) = 10
Let m^y = t
=> t + 1/t = 10
=> t^2 - 10t + 1 = 0
=> t = (1/2) (10 ± 4v6) = 5 ± 2v6
=> m^(x^2 -3) = 5 ± 2v6 = m or m^-1
=> x^2 -3 = 1 or -1
=> x^2 = 4 or 2
=> x = ±2 or ±v2
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Question 30.
An experiment is performed to verify Ohm’s law using a resister of resistance R = 100O, a battery of variable potential difference, two galvanometers and two resistances of 106O and 10-3O are given. Draw the circuit diagram and indicate clearly position of ammeter and voltmeter.
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Question 31.
A point object is moving with velocity 0.01 m/s on principal axis towards a convex lens of focal length 0.3m. When object is at a distance of 0.4 m from the lens, find
(a) rate of change of position of the image, and
(b) rate of change of lateral magnification of image.
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Question 32.
A spherical ball of radius R, is floating in a liquid with half of its volume submerged in the liquid. Now the ball is displaced vertically by small distance inside the liquid. Find the frequency of oscillation of ball.
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Question 33.
In a photoelectric setup, the radiations from the Balmer series of hydrogen atom are incident on a metal surface of work function 2eV. The wavelength of incident radiations lies between 450 nm to 700 nm. Find the maximum kinetic energy of photoelectron emitted.
(Given hc/e = 1242 eV-nm).
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Question 34.
A small ball of radius ‘r’ is falling in a viscous liquid under gravity. Find the dependency of rate of heat produced in terms of radius ‘r’ after the drop attains terminal velocity.
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Question 35.
In Searle’s apparatus diameter of the wire was measured 0.05 cm by screw gauge of least count 0.001 cm. The length of wire was measured 110 cm by meter scale of least count 0.1 cm. An external load of 50 N was applied. The extension in length of wire was measured 0.125 cm by micrometer of least count 0.001 cm. Find the maximum possible error in measurement of young’s modulus.
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Question 36.
An ideal diatomic gas is enclosed in an insulated chamber at temperature 300K. The chamber is closed by a freely movable massless piston, whose initial height from the base is 1m. Now the gas is heated such that its temperature becomes 400 K at constant pressure. Find the new height of the piston from the base.
If the gas is compressed to initial position such that no exchange
of heat takes place, find the final temperature of the gas.
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Question 37.
Write balanced chemical equation for developing a black and white photographic film. Also give reason why the solution of sodium thiosulphate on acidification turns milky white and give balance equation of this reaction.
Answer: When a PHOTOGRAPHIC FILM is treated with HYPO,the AgCl on the film reacts with the Na2S2O3 n forms a complex Na3[Ag(S2O3)] along with NaBr.
Hence the reaction is AgCl+Na2S2O3------->Na3[Ag(S2O3)]+NaBr.
When HYPO is reacted with SULPHURIC ACID,it forms Sodium Sulphate along with Sulphurdioxide and Sulphur along with water.
Na2S2O3+2H2SO4------->Na2SO4+SO3+S+4H2O
Is it correct??
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Question 38.
An element crystallizes in fcc lattice having edge length 400 pm. Calculate the maximum diameter of atom which can be placed in interstitial site without distorting the structure.
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Question 39.
If the cathode is a Hg electrode, the maximum weight (g) of amalgam formed from this solution is
(A) 200
(B) 225
(C) 400
(D) 446
Answer: D is correct
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Question 40.
Extraction of zinc from zinc blende is achieved by
(A) electrolytic reduction
(B) roasting followed by reduction with carbon
(C) roasting followed by reduction with another metal
(D) roasting followed by self-reduction
Answer: B is correct option
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Question 41.
STATEMENT-1
In an elastic collision between two bodies, the relative speed of the bodies after collision is equal to the relative speed before the collision.
because
STATEMENT-2
In an elastic collision, the linear momentum of the system is conserved.
(A) Statement -1 is True, Statement-2 is True; Statement -2 is a correct explanation for Statement-1.
(B) Statement -1 is True, Statement-2 is True; Statement -2 is NOT a correct explanation for Statement-1.
(C) Statement -1 is True, Statement-2 is False.
(D) Statement -1 is False, Statement-2 is True.
Answer: B is correct
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Question 42.
STATEMENT-1
A block of mass m starts moving on a rough horizontal surface with a velocity v. It stops due to friction between the
block and the surface after moving through a certain distance. The surface is now tilted to an angle of 300 with the horizontal and the same block is made to go up on the surface with the same initial velocity v. The decrease in the
mechanical energy in the second situation is smaller than that in the first situation.
because
STATEMENT-2
The coefficient of friction between the block and the surface decreases with the increase in the angle of inclination.
(A) Statement -1 is True, Statement-2 is True; Statement-2 is a correct explanation for statement-1.
(B) Statement -1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for statement-1.
(C) Statement -1 is True, Statement-2 is False.
(D) Statement -1 is False, Statement-2 is True.
Answer: C is correct
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Question 43.
STATEMENT-1
If the accelerating potential in an X-ray tube is increased, the wavelengths of the characteristic X-rays do not change.
because
STATEMENT -2
When an electron beam strikes the target in an X-ray tube, part of the kinetic energy is converted into X-ray energy.
(A) Statement-1 is True, Statement-2 is True; Statement -2 is a correct explanation for Statement-1.
(B) Statement-1 is True, Statement-2 is True; Statement -2 is NOT a correct explanation for Statement-1.
(C) Statement -1 is True, Statement-2 is False.
(D) Statement -1 is False, Statement-2 is True.
Answer: B is correct
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Question 44.
STATEMENT-1
The formula connecting u, v and f for a spherical mirror is valid only for mirrors whose sizes are very small compared
to their radii of curvature.
because
STATEMENT-2
Laws of reflection are strictly valid for plane surfaces, but not for large spherical surfaces.
(A) Statement-1 is True, Statement-2 is True; Statement -2 is a correct explanation for Statement-1.
(B) Statement-1 is True, Statement-2 is True; Statement -2 is NOT a correct explanation for Statement-1.
(C) Statement -1 is True, Statement-2 is False.
(D) Statement -1 is False, Statement-2 is True.
Answer: C is correct Answer
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Question 45.
Consider a neutral conducting sphere. A positive point charge is placed outside the sphere. The net charge on the sphere is then,
(A) negative and distributed uniformly over the surface of the sphere
(B) negative and appears only at the point on the sphere closest to the point charge
(C) negative and distributed non-uniformly over the entire surface of the sphere
(D) zero
Answer: D
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Question 46.
A ray of light travelling in water is incident on its surface open to air. The angle of incidence is ?, which is less than the critical angle. Then there will be
(A) only a reflected ray and no refracted ray
(B) only a refracted ray and no reflected ray
(C) a reflected ray and a refracted ray and the angle between them would be less than 180° - 2?
(D) a reflected ray and a refracted ray and the angle between them would be greater than 180° - 2?
Answer: C
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Question 47.
A resistance of 2 O is connected across one gap of a metre-bridge (the length of the wire is 100 cm) and an unknown resistance, greater than 2O, is connected across the other gap. When these resistance are interchanged, the balance point
shifts by 20 cm. Neglecting any corrections, the unknown resistance is
(A) 3 O
(B) 4 O
(C) 5 O
(D) 6 O
Answer: (A)
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Question 48.
The largest wavelength in the ultraviolet region of the hydrogen spectrum is 122 nm. The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is
(A) 802 nm
(B) 823 nm
(C) 1882 nm
(D) 1648 nm
Answer: (B)- Transition from 8 to n = 3 will produce smallest wavelength in infrared region.
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Question 49.
In an experiment to determine the focal length (f) of a concave mirror by the u–v method, a student places the object pin A on the principal axis at a distance x from the pole P. The student looks at the pin and its inverted image from a
distance keeping his/her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the right of the object pin. Then
(A) x < f
(B) f < x < 2f
(C) x = 2f
(D) x > 2f
Answer: B - Due to parallax
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