"OM SAI RAM "
SPECTRUM CLASSES. Physics Class XI
1.Why is it desired to hold a gun
tight to one’s shoulder when it is being fired?
2. Why does a swimmer push the
water backwards?
3. Friction is a self adjusting
force. Justify.
4. A force is being applied on a
body but it causes no acceleration. What possibilities may be considered to
explain the observation?
5. Force of 10 N and 12N are
acting on a mass of 300 kg in mutually perpendicular directions. Find the
magnitude of the acceleration produced?
6. An elevator weighs 4000kg. What
is its acceleration when the in the tension supporting cable is 30000N. Given
that g = 10 m/s2.
7. Write two consequences of
Newton’s second law of motion?
8. How is centripetal force
provided in case of the following?
(i) Motion of planet around the sun,
(ii) Motion of moon around the earth.
(iii) Motion of an electron around the nucleus in an
atom.
9. State Newton’s second, law of
motion. Express it mathematically and hence obtain
a relation between force and acceleration.
10. A railway car of mass 30 tonnes
moves with an initial speed of 108 km/hr. On
applying brakes, a constant negative acceleration of
0.5m/s2 is produced.
(i) What is the breaking force acting on the car?
(ii) In what time it will stop?
(iii) What distance will be
covered by the car before if finally stops?
11.Draw a graph showing static ,
limiting and kinetic friction ?
12. Define Light year and
Astronomical unit with its numerical values.
13. Define power with its SI unit.
14. Two bodies A and B having masses
5 kg and 6 kg respectively, have there equal kinetic energy. Find ratio of their momentum.
15. Explain Surface tension , with
its one example.
16. The pressure P=F/A, where F =100
± 5 pascal and A =10 ± 0.2 m2.Find the percentage error in P.
17. Newton’s Second law of motion is the real law of motion ,
Explain.
18.State and prove work energy theorm.
19. Derive the equation by
calculus method
V2-u2=2as
Where symbol has their usual meanings
20. What do you mean by
banking of road and derive the expression for the optimum velocity.
(a)State and prove triangles
law of vectors addition.
21. Having seen a big stone
falling from the top of a tower Ravi pulled his friend Kiran away. The stone
hit Ravi slightly and he got hurt. But he was saved from a major accident.
(a)What made Ravi act in such a way. (b)From the top of a tower 100 m in height,
a ball is dropped and at the same time another ball is projected vertically
upwards from the ground with a velocity of 25 m/s.Find when and where the two
balls meet.
Take g = 9.8 m/sec2.(Value Based Question)
22. In which motion linear
momentum changes but K.E does not?
23. What is the S.I unit and
dimensional formula for plancks constant?
towards each other. Why?
24. When air is blown between two
balls suspended closed to each other. They are attracted
25.
Write the number of significant figures in (a) 2.64 × 1024 kg (b) 0.00786 g/cm3
26. Show that impulse of a force is
equal to change in linear momentum produced by the force.
27.State Newton’s second law of
motion on its basis derived the relation between force and acceleration.
28. why is it easier to pull than to
push a body ?
29. Write the dimension of aXb in
the relation.
F=ax + bt2, where F is force, x is
distance and t is time.
30. A particle is projected with
velocity u making an angle with the horizontal direction. Write formula for:
(a) Time of Flight
(b) Horizontal Range
31. Two bodies A and B having
masses 5 kg and 6 kg respectively, have there equal momentum. Find ratio
of their Kinetic energies.
32. What do you mean by
bending of cyclist and derive the expression for the angle of bending.
33. A truck and car moving
with same K.E are stooped by applying same retarding force by means of breakers
which will stop at a small distance?
34.Define elastic collision.
Prove that bodies of identical masses exchange their velocities s after head on
collision.
35. define centripetal
acceleration. Derive an expression for the centripetal acceleration of a body
moving with uniform speed v along a circular path of radius r.
36.In projectile, a particle
is projected such that magnitude of velocity at topmost point is half of the
magnitude of initial velocity. Find the angle of projectile.
37.State and Prove law of
parallelogram.
38.A projective can have the
same Range R for two angles of projection. If t1 and t2 be the time of flight
in the two cases then prove that:
T1T2=2R/g
39. State and prove law of conservation of linear
momentum.
40. A machine has a mass of
20kg. It fires 35gm bullets at the rate of 4 bullets per second , with the
speed of 400 m sec-1.what force must be applied to the gun to keep it in
position ?
41.
Write the laws of limiting friction.Show the angle of friction is numerically
equal to angle of repose
42. A bus moving with a speed
of 36 km hr-1 negotiates a level circular road of radius 10 m .What should be
the coefficient of friction so that the bus may not skit of the road?
43. If the Kinetic Energy of a body increases by 300%, by what
% will the linear momentum of the body increase?
44. The resistance R=V/I, where V
=100 ± 5 V and I =10 ± 0.2 A.Find the percentage error in R.
45.Suraj went to Big Bazaar to
purchase certain goods .There he has noticed an old lady struggling with her
shopping. Immediately he showed her the lift and explained to her how it
carries the load from one floor to the next. Even then the Old lady was not
convinced.. Then suraj took her in the lift and showed her how to operate it..
That old lady was very happy. (a)What values does Suraj possess? (b)An elevator
can carry a maximum load of 1800 kg is moving up with a constant speed of 2 m/s
, The frictional force opposing the motion is 4000 N. Determine the minimum
power delivered by the motor to the elevator in watts as well as in horse
power. (Value Based Question)
47. Rakesh with the intention to win
in the interschool sports practiced high jump every day for about a month. He
participated and won I position in the interschool sports. (a) Comment upon the
values Rakesh possesses. (b) Why does an athlete run some steps before taking a
jump? (Value
Based Question)
48 Find the scalar and vector
product between vectors A=3i - 2j + 4k
and B = 2i - 4j + 3k.
49. A monkey is sitting on a
tree. Rahim seeing the Monkey brought some fruits and gave them to the Monkey,
and ran into the house immediately. On hearing the sound produced when Rahim
was running the monkey was scared and climbed the nearby tree.
(a) What values of Rahim
inspired you?
(b)A monkey of mass 40 Kg
climbs on a rope which can stand a maximum tension of 600 N .
In which of the following cases
will the rope will break. The monkey
(I) Climbs up with an
acceleration of 6 m/s2
(II) Climbs down with an
acceleration of 4 m/s2
(III) Climbs up with a uniform
speed of 5 m/s
(IV) Falls down the rope nearly
under gravity?
(Take g= 10 m/s2) (Ignore the
mass of the rope) (Value Based Question)
50. A bullet of mass 0.04 kg moving
with a speed of 90 m s-1 enters a heavy wooden block and is stopped
after a distance of 60 cm. What is the average resistive force exerted by the
block on the bullet?
51. The motion of a particle of mass
m is described by y = ut + 1/2 gt2 Find the force
acting on the particle.
52. A batsman hits back a ball
straight in the direction of the bowler without changing its initial speed of
120 m s–1. If the mass of the ball is 0.15 kg, determine the impulse imparted
to the ball. (Assume linear motion of the ball)
53. A circular racetrack of radius
300 m is banked at an angle of 15°. If the coefficient of friction between the
wheels of a race-car and the road is 0.2, what is the (a) optimum speed of the
racecar to avoid wear and tear on its tyres, and (b) maximum permissible speed
to avoid slipping ?
54. A cyclist speeding at 18 km/h on
a level road takes a sharp circular turn of radius 3 m without reducing the
speed. The co-efficient of static friction between the tyres and the road is
0.1. Will the cyclist slip while taking the turn ?
55. A wooden block of mass 2 kg
rests on a soft horizontal floor. When an iron cylinder of mass 25 kg is placed
on top of the block, the floor yields steadily and the block and the cylinder
together go down with an acceleration of 0.1 m s–2.
What is the action of the block on the floor (a) before and (b) after the floor
yields ? Take g = 10 m s–2. Identify the action-reaction pairs in the
problem.
56. The driver of a three-wheeler
moving with a speed of 36 km/h sees a child standing in the middle of the road
and brings his vehicle to rest in 4.0 s just in time to save the child. What is
the average retarding force on the vehicle ? The mass of the three-wheeler is
400 kg and the mass of the driver is 65 kg.
57. A bob of mass 0.1 kg hung from
the ceiling of a room by a string 2 m long is set into oscillation. The speed
of the bob at its mean position is 1 m s-1. What is the trajectory of the bob
if the string is cut when the bob is (a) at one of its extreme positions, (b)
at its mean position.
58. A man of mass 70 kg stands on a
weighing scale in a lift which is moving
(a) upwards with a uniform speed of 10 m s-1,
(b) downwards with a uniform acceleration of 5 m s-2,
(c) upwards with a uniform acceleration of 5 m s-2.
What would be the readings on the scale in each
case?
(d) What would be the reading if the lift mechanism
failed and it hurtled down freely under gravity ?
59. Two masses 8 kg and 12 kg are
connected at the two ends of a light inextensible string that goes over a
frictionless pulley. Find the acceleration of the masses, and the tension in
the string when the masses are released.
60. A shell of mass 0.020 kg is fired by a gun of mass
100 kg. If the muzzle speed of the
shell is 80 m s-1, what is the recoil speed of the
gun ?
61. A batsman deflects a ball by an
angle of 45° without changing its initial speed which is
equal to 54 km/h. What is the impulse imparted to
the ball ? (Mass of the ball is 0.15 kg.)
62. A stone of mass 0.25 kg tied to
the end of a string is whirled round in a circle of radius 1.5 m with a speed
of 40 rev./min in a horizontal plane. What is the tension in the string ? What
is the maximum speed with which the stone can be whirled around if the string
can withstand a maximum tension of 200 N ?
63. Explain why
(a) a horse cannot pull a cart and run in empty
space,
(b) passengers are thrown forward from their seats
when a speeding bus stops
suddenly,
(c) it is easier to pull a lawn mower than to push
it,
(d) a cricketer moves his hands
backwards while holding a catch.
64. A helicopter of mass 1000 kg
rises with a vertical acceleration of 15 m s-2. The crew
and the passengers weigh 300 kg. Give the magnitude
and direction of the
(a) force on the floor by the crew and passengers,
(b) action of the rotor of the helicopter on the
surrounding air,
(c) force on the helicopter due
to the surrounding air.
65. A train runs along an unbanked circular track of
radius 30 m at a speed of 54 km/h.
The mass of the train is 106 kg. What provides the
centripetal force required for this
purpose — The engine or the rails ? What is the
angle of banking required to prevent
wearing out of the rail ?
66. A monkey of mass 40 kg climbs on
a rope (Fig. 5.20) which can stand a maximum tension of 600 N. In which of the
following cases will the rope break: the monkey
(a) climbs up with an acceleration of 6 m s-2
(b) climbs down with an acceleration of 4 m s-2
(c) climbs up with a uniform speed of 5 m s-1
(d) falls down the rope nearly
freely under gravity?
67. A block of mass 15 kg is placed
on a long trolley. The coefficient of static friction between the block and the
trolley is 0.18. The trolley accelerates from rest with 0.5 m s-2
for 20 s and then moves with uniform velocity. Discuss the motion of the block
as viewed by (a) a stationary observer on the ground, (b) an observer moving
with the trolley.
68. The rear side of a truck is open and a box of 40 kg
mass is placed 5 m away from the open end as shown in Fig The coefficient of
friction between the box and the surface below it is 0.15. On a straight road,
the truck starts from rest and accelerates with 2 m s-2. At what
distance from the starting point does the box fall off the truck? (Ignore the
size of the box)
69.
Ten one-rupee coins are put on top of each other on a table. Each coin has a
mass m.
Give the magnitude and direction of
(a) the force on the 7th coin (counted from the
bottom) due to all the coins on its top,
(b) the force on the 7th coin by the eighth coin,
(c) the reaction of the 6th coin
on the 7th coin.
70. A stone of mass 0.25 kg tied to
the end of a string is whirled round in a circle of radius 1.5 m with a speed
of 40 rev./min in a horizontal plane. What is the tension in the string ? What
is the maximum speed with which the stone can be whirled around if the string
can withstand a maximum tension of 200 N ?
71. Radha found the wheel getting
detached from her uncle’s car . She took it to workshop and got it repaired.
She informed her uncle, who is a mechanical engineer, about this matter. (a)
What according to you the values displayed by Radha? (b)A thin wheel can stay
up-right on its rim for a considerable length of time when rolled with a
considerable velocity, while it falls from its upright position at the
slightest disturbance, when stationery. Explain. ( Value Based
Question)
72. Suresh noticed a big Granite
Rock in his locality. He thought that if they worked upon it they could earn
money. He took permission from the Government, completed all the formalities
.He broke the Rock using a bomb. The rock was made into slices .They established
a Granite industry. Many of the people in the surroundings started to earn and
live comfortably. (a) What values of Suresh impress you? (b)A bomb is thrown in
a horizontal direction with a velocity of 50 m/s. It explodes into two parts of
masses 6 Kg and 3 Kg. the heavier fragment continues to move in the horizontal
direction with a velocity of 80 m/s .Calculate the velocity of the lighter
fragment. .( Value Based Question)
73. A 2 kg ball on a string is
rotated about a circle of radius 10 m. The maximum tension allowed in the
string is 50 N. What is the maximum speed of the ball?
74. A satellite is said to be in
geosynchronous orbit if it rotates around the earth once every day. For the
earth, all satellites in geosynchronous orbit must rotate at a distance of 4.23×107 meters from the earth's center. What is
the magnitude of the acceleration felt by a geosynchronous satellite?
75.The maximum lift provided by a
500 kg airplane is 10000 N. If the plane travels at 100 m/s, what is its
shortest possible turning radius?
76.Prove that the angular projectile
form parabolic path , derive expression for time of flight , range and height
of projectile.
77.Prove the relation between
linear speed and angular velocity V = r
ω
78. A machine has a mass of
20kg. It fires 35gm bullets at the rate of 4 bullets per second , with the
speed of 400 m sec-1.what force must be applied to the gun to keep
it in position ?
79.Derive the expression Snth
= u + a/2(2n-1)
80.Write the number of
significant figures in (a) 2.64 × 1024 kg (b) 0.00786 g/cm3
81.Can two streamline cross
each other in flowing liquid ? Explain.
82. In which motion linear
momentum changes but K.E does not?
83. What is the time period of
simple pendulum at the centre of the earth and in the space ?
84. What is the S.I unit and
dimensional formula for plancks constant?
85. Why is difficult to stop
bleeding from cut in human body at high altitudes?
86. When air is blown between
two balls suspended closed to each other. They are attracted towards each
other. Why?
87. What will be the effect on
the duration of a day on earth, if the earth suddenly contracts?
88. If the radius of the earth
shrinks by 5%, mass remaining same , then how would the value of acceleration
due to gravity change?
89. Show that impulse of a
force is equal to change in linear momentum produced by the force.
90. Two bodies A and B having
masses 5 kg and 6 kg respectively, have there equal momentum. Find ratio
of their Kinetic energies.
91. Air is pushed into a soap
bubble of radius r to double its radius , if the surface tension of the
soap solution is S ,find the workdone.
92.
The resistance V=W/Q, where W =10 ± 2 J and Q =100 ± 0.2 C.Find the percentage
error in V. 93.Explain why hollow shaft
is Stronger than solid shaft.
94. A machine has a mass of
25kg. It fires 20 gm bullets at the rate of 24 bullets per minute , with the
speed of 300 m sec-1.what force must be applied to the gun to keep
it in position ?
95. Define Cp and Cv
and Derive the relation between them..
96. Eight rain drops of radius
1mm. each falling down with the terminal velocity of 5 cm/s combine to form a
bigger drop. Find the terminal velocity of bigger drop.
97. What do you mean by bending
of cyclist and derive the expression for the angle of bending.
98.Show the motion of a liquid
in a U-tube is simple harmonic, find an expression for its time period.
99. Write the formula for
Kinetic energy, Potential energy and total energy of a body executing SHM.
Prove that energy that energy is directly proportional to square of amplitude
and frequency.
100.Define three coefficients of expansion α, β and γ and derive relation between them..
101. Explain the construction and
various operations for an ideal carnot heat engine working between two
temperatures and define its efficiency .
102.State and prove Bernoulli’s
theorem.
103.Derive expression for ascent formula (Rise of liquid in capillary
tube ) , what happen if tube is of insufficient length.
104..How much heat energy is
required to heat 1 kg of water at 20 ⁰C to 100 ⁰C?
105.A water pipe entering a
holes has a diameter of 4 cm and the speed of water is 0.5 m/s. Eventually, the
pipe tappers the diameter of 2cm.Calculate the speed of water in the trap
portion.
106. Suraj went to Big Bazaar
to purchase certain goods .There he has noticed an old lady struggling with her
shopping. Immediately he showed her the lift and explained to her how it
carries the load from one floor to the next. Even then the Old lady was not
convinced.. Then suraj took her in the lift and showed her how to operate it..
That old lady was very happy. (a)What values does Suraj possess? (b)An elevator
can carry a maximum load of 1800 kg is moving up with a constant speed of 2 m/s
, The frictional force opposing the motion is 4000 N. Determine the minimum
power delivered by the motor to the elevator in watts as well as in horse
power.(Value Based Question) .
107.On which principle does
following thing work (a) Aeroplane (b) Computer (c) Endoscopy
(d) Optical fibre (e) ECG (f)
Full Form Of LASER.
108. Explain Newton’s law of
cooling and draw curve for it.
109. Explain zeroth law , first
law and second law of thermodynamics .
110.Exlpain the working of a
heat engine with diagram and what do you understand by efficiency of a heat
engine.
111. What is degrees of freedom
, explain degrees of freedom of mono atomic , diatomic and tri atomic gases.
112. What do you understand by
law of equipartition of energy .
113. Derive the expression for
pressure of an ideal gas .
114. Derive ideal gas equation
PV = nRT.
115. Why cold air comes out
after bursting of a tyre explain.
116.Difference between longitudinal
and transverse wave.
117. Explain interference of
waves and its types.
118.Explain the factors
affecting speed of sound .
119. Difference between
internal and external combustion engine .
120.what is a refrigerator ,
explain its working and define coefficient of performance for it , why we can’t
use CFC as a refrigerant.
121.Why Cp is always greater
than Cv.
122.Explain the working of
hydraulic brake and lift by a diagram.
123. Define effective length for a simple pendulum. If we
increase the mass of bob of a pendulum
,what is the effect on its time period.
124. Show the motion of a simple pendulum follows S.H.M
with its derivation.
125. At what distance from the mean position is the K.E in
SHM equal to P.E
126. Explain Hooke’s law and
draw stress -strain curve for it.
127. The Displacement equation
for a particle in SHM is given by y = 0.01 sin100Π(t + 0.005) meter find its
(a) Amplitude (b) time period (c) Maximum Velocity (d) Displacement at the time
of start.(e) Phase Difference
128. The equation of a
progressive wave is given by y = 0.05 sin2Π/3(t + 0.02 x) find wave length ,
wave speed , frequency , amplitude , propagation constant.
129. Explain the construction
and various operations for an ideal carnot heat engine working between two
temperatures and define its efficiency .
130. Explain Magnus Effect with
its diagram.
131. If the average
temperature of the body is found to be 37 C, then what it will be in
Fahrenheit?
132. Prove that the
elastic potential energy density of a stretched wire is equal to half the product of stress and strain.
133.Why a diver under water is unable to hear a sound produced
in air?
134. The soldiers marching on a suspended bridge are advised
to go out of steps. Why ?
135. Explain why
(a) To keep a piece of paper horizontal, you should blow over,
not under, it.
(b) When we try to close a water tap with our fingers, fast
jets of water gush
through the openings between our fingers.
136. Write the formula for Kinetic energy, Potential energy
and total energy of a body executing SHM. Prove that energy that energy is
directly proportional to square of amplitude and frequency.
137. Why pillars used in
buildings usually have distributed ends?
138. All periodic motion is not
harmonic in nature. Justify.
139.
A block of mass 2kg rests on a rough inclined plane making an angle 30° with
the horizontal. The coefficient
of friction between the block and the plane is 0.7.
What will be the frictional
force on the block?
140.
A reversible engine converts 1/6 of heat input into work. When the temperature
of the sink is reduced by 62 c,
its efficiency is doubled. Find the temperature of
the source and the sink.
141.
A satellite is revolving around a planet of mass min a fixed circular orbit of
radius r. find the expression for
its
(1) Angular momentum and
(2) kinetic energy?
142.
An aircraft is flying at a height of 3400 m above the ground. If the angle
subtended
at a ground observation point by
the aircraft positions 10.0 s apart is 30°, what is the
speed of the aircraft?
143. A pump on the ground floor of a building can pump up
water to fill a tank of volume
30 m3 in 15 min. If
the tank is 40 m above the ground, and the efficiency of the pump
is 30%, how much electric power
is consumed by the pump?
144. A solid cylinder rolls up an inclined plane of angle
of inclination 30°. At the bottom
of the inclined plane the
centre of mass of the cylinder has a speed of 5 m/s.
(a) How far will the cylinder
go up the plane?
(b) How long will it take to
return to the bottom?
145. A spring having with a spring constant 1200 N m–1 is
mounted on a horizontal
table as shown in Fig. A mass
of 3 kg is attached to the free end of the spring.
The mass is then pulled
sideways to a distance of 2.0 cm and released.
Determine (a) the frequency of
oscillations, (b) maximum acceleration of the
mass, and (c) the maximum speed
of the mass.
146. A mass = m suspend separately from two springs of spring
constant k1
and k2 gives time period t1
and t2 respectively. If
the same
mass is connected to both the springs as shown in
figure. Calculate the time period ‘t’ of the combined system?
147. Why do the
stages of large auditoriums gave curved backs?
148. Calculate the work done during the isothermal and adiabatic
Process ?
149. What is the ratio of find volume to initial volume if the gas is
compressed
adiabatically till its temperature is doubled?
150. A sports teacher was
training the children for march-past. On their way they come across a bridge
.Then the physical education teacher stopped the children from marching on the
bridge.
(a)
Comment upon the values of sports teacher. b) Also explain what is meant by
Resonance.
Er.SHYAM PACHORI
C.L 157 D.D NAGAR
Er.SHYAM PACHORI
C.L 157 D.D NAGAR
MOB:9039803981
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