A force of 5 N making an angle 8 with the horizontal acting on an object displaces it by 0.4 m along the horizontal direction. If the object gains kinetic energy of 1 J the horizontal component of the force is :
1.5 N
2.5 N
3.5 N
4.5 N
The frequency of the sound of a car horn as recorded by an observer towards whom the car is moving differs from the frequency of the horn by 10%.Assuming the velocity of sound in air to be 330ms-1,the velocity of the car is
36.7ms-1
40ms-1
30ms-1
33ms-1
Δλ is the difference between the wave length of kα line and the minimum wavelength of the continuous X-ray spectrum when the X-ray tube is operated at a voltage V. If the operating voltage is changed to v/3 , then the above difference is Δλ'. Then :
Δλ'=5Δλ
Δλ'=4Δλ
Δλ'=3Δλ
Δλ'
A step down transformer has a supply line voltage of 2200V in to 220V. The primary coil has 5000 turns. The efficiency and power transmitted by the transformer are 90% and 8 kilowatt respectively. Then the number of turns in the secondary is
5000
50
500
5
Two wires of the same material but of different diameters carry the same current I. If the ratio of their diameters is 2 : 1, then the corresponding ratio of their mean drift velocities will be
4 : 1
1 : 1
1 : 2
1 : 4
Four bulbs each marked 40 W. 250 V are connected in series with 250 V source. The total power output is
10 W
40 W
160 W
320 W
Two cylinders A and B fitted with pistons, contain equal number of moles of an ideal mono atomic gas at 400 K. The piston of A is free to move while that of B is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in A is 42 K, the rise in temperature of thegas in B is (γ = 5/3)
25.2 K
35 K
42 K
70 K
The velocity of a listener who is moving away from a stationary source of sound such that the listener notices 5% apparent decrease in frequency of sound is(Velocity of sound in air=340ms-1)
12.5ms-1
17ms-1
25ms-1
34ms-1
A light ray is incident on a transparent medium of μ=1.732 at the polarizing angle.The angle of refraction is
900
450
300
600
Two point charges -q and +q are located at points (0, 0, -a) and (0, 0, a) respectively. The electric potential at a point (0, 0, z), where z > a
qα/ 4πεoz2
q/ 4πεoα
2qα/ 4πεo (z2 - a2 )
2qα/ 4πεo (z2 + a2 )
A condenser 1μF is charged to a potential of 1000 volt. The energy stored in the condenser is:
1J
10-3 J
0.5 J
10-6 J
Two waves of wavelengths 2m and 2.02m respectively moving with the same velocity superpose to produce 2 beats/s.The velocity of the wave is
400m/s
402m/s
404m/s
406m/s
The displacement of a particle moving in a straight line is given by x = 2t2+t+5 where x is expressed in meter and 't' in second.The acceleration at t = 2sec is
4 m/s2
8 m/s2
10 m/s2
15 m/s2
A primary coil and secondary coil are placed close to each other. A current, which changes at the rate of 25 amp in a millisecond, is present in the primary coil. If the mutual inductance is 92x10-6 Henries,then the value of induced emf in the secondary coil is
4.6 V
2.3 V
0.368 mV
0.23 mV
A compound slab is made with two different materials A and B with coefficient of thermal conductivity KA = 2KB and thickness XA=(1 / 2) XB. If the face of the A surface is at 1000C and that of the B surface is at 250C the temperature of the common surface will be
850C
450C
400C
150C
A particle of mass 4 m explodes into three pieces of masses m, m and 2 m. The equal masses move along X- and Y-axes with velocities 4 ms-1 and 6 ms-1 respectively. The magnitude of the velocity of the heavier mass is
√17 ms-1
2√13 ms-1
√13 ms-1
√13 / 2 ms-1
A charge of 10 units is divided so that force between the two charges is maximum when placed 2cm apart. The two charges are
5,5
1,9
3,7
6,4
Power radiated by a black body at temperature T1 is P and it radiates maximum energy at a wavelength λ1.If the temperature of the black body is changed from T1toT2,it radiates maximum energy at a wavelength λ1/2.The power radiated at T2 is
2P
4P
8P
16P
Two straight long parallel conductors carrying different currents are separated by a distance 20 cm in air such that force per unit length on each conductor is 5 x 10-3 N/m If the current in first conductor is 50 A then the current in the second conductor is:
25 A
75 A
100 A
125 A
The angle of minimum deviation when light is incident at an angle of 450 on the refracting faces of an equilateral prism of refractive index 1.414 is
400
A whistling engine is approaching a stationary observer with a velocity of 110m/s. The velocity of sound is 330m/s. The ratio of frequencies as heard by the observer as the engine approaches and recedes is
2:1
3:6
4:1
4:3
The temperature of the system decreases in the process of
free expansion
adiabatic expansion
isothermal expansion
isothermal compression
Apparent frequency of sound is 505 Hz when the listener is approaching a stationary source of sound with a velocity 1% of the velocity of sound in air. The actual frequency of sound is
500 Hz
490 Hz
480 Hz
470 Hz
A parallel plate capacitor has a capacitance of 10 micro farads without dielectric. A dielectric of dielectric constant 2 is used to fill exactly half the thickness between the plates. The capacitance in micro farads,now is
10
20
15
13.33
A free neutron decays spontaneously into :
a proton, an electron and anti-neutrino
a proton, an electron and a-neutrino
a proton and electron
a proton, and electron, a neutrino and an anti-neutrino
The de Broglie wavelength of an electron moving with a velocity of 1.5x108m/s is equal to that of a photon. The ratio of kinetic energy of the electron to that of the photon (C=3x108m/s)
2
4
1/2
1/4
Two point charges are separated by 3 cm of air and 3 cm of a dielectric of relative permittivity 4.The equivalent air separation between them is (as far as their coulombic interaction is concerned)
6 cm
9 cm
12 cm
15 cm
An observer is moving away from a sound source of frequency 100Hz. If the observer is moving with a velocity 49m/s and the speed of sound in air is 330m/s. The observed frequency is:
85Hz
91Hz
100Hz
149Hz
When an unknown resistance of 4Ω are connected in the left and right gaps of a meterbridge,the balance point is obtained at 50cm.The shift in the balance point if a 4 Ω resistance is now connected in parallel to the right gap is
14.6cm
34.6cm
16.7cm
66.7cm
Two tuning forks of frequencies 250 and 256 Hz produce beats.If maximum is produced now,thus the minimum time after which minimum is produced at that same place
(1/18)s
(1/24)s
(1/6)s
(1/12)s
In an experiment of photoelectric emission, for incident light of 4000A0, stopping potential is 2V. If the wavelength of incident light is made 3000A0, then the stopping potential will be
Less than 2V
More than 2V
2V
zero
A source producing sound of frequency 170 Hz is approaching a stationary observer with a velocity of 17 ms-1. The apparent change in the wavelength of sound heard by the observer is: (speed of sound in air=340ms-1)
0.1 m
0.2 m
0.4 m
0.5 m
Two positive charges 12μC and 10μC are initially separated by 10cm.The work done in bringing the two charges 4cm closer is
7.2J
3.6J
8.4J
12.4J
An object of mass 2 m is projected with a speed of 100 ms-1 at an angle θ = sin-1 (3/5) to the horizontal. At the highest point, the object breaks into two pieces of same mass m and the first one comes to rest. The distance between the point of projection and the point of landing of the bigger piece (in meter) is (Given g =10 m/s2)
3840
1280
1440
960
Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-clad interface.Reason (R): Refractive index of the material of the core of the optical fibre is greater than that of air.
both (A) and (R) are true and (R) is the correct explanation of (A)
both (A) and (R) are true but (R) is not the correct explanation of (A)
(A) is true but (R) is false
(A) is false but (R) is true
In a photoelectric cell, wavelength of the incident light is changed from 4000A0 to 3600A0. Change in stopping potential will be nearly
0.14V
0.24V
0.34V
0.44V
A transverse wave propagating on a stretched string of linear density 3x10-4kgm-1 is represented by the equation y=0.2sin(1.5x+60t) where x is in meter and t is in seconds. The tension in the string in N.
1.80
1.20
0.48
0.24
Two concentric circular coils A and B have radii 25cm and 15cm and carry currents 10A and 15A respectively.A has 24 turns and B has 18 turns.The direction of currents are in opposite order.The magnetic induction at the common centre of the coil is
μo
420μoT
480μoT
120μoT
The tyre of a motor car contains air at 150C. If the temperature increases to 350C, the approximate percentage increase in pressure is (ignore to expansion of tyre)
7
9
11
13
A 2 kg mass moving on a smooth frictioriless surface with a velocity of 10 m/s, hits another 2 kg mass kept at rest in an elastic collision. After collision, if they move together:
they travel with a velocity of 5 ms-1 in the same direction
they travel with a velocity of 10 ms-1 in the same direction
they travel with a velocity of 10 ms-1 in the opposite direction
they travel in the opposite direction with a velocity of 5 ms-1
Two identical piano wires have a fundamental frequency of 600 c/s when kept under the same tension. What fractional increase in the tension of one wire will lead to the occurrence of 6 beats per second when both wires vibrate simultaneously
0.01
0.02
0.03
0.04
In a potentiometer experiment, when a resistance of 10 ohm is connected in parallel to the cell in secondary circuit , the balancing length is 350 cm. when 10 ohm resistance is replaced by 20 ohm resistance, the balancing length becomes 420 cm.The internal resistance of the cell in secondary circuit is
5 ohm
7.5 ohm
10 ohm
12.5 ohm
A body of mass 5 kg makes an elastic collision with another body at rest and continues to move in the original direction after collision with a velocity equal to 1/10th of its original velocity. Then the mass of the second body is
4.09 kg
0.5 kg
5 kg
5.09 kg
The resistance of a conductor is 1.08Ω.To reduce it to 1Ω,the resistance that must be connected is
0.08Ω in series
13.5 Ω in parallel
0.08 Ω in parallel
13.5Ω in series
The two lenses of an achromatic doublet should have
equal powers
equal dispersive powers
equal ratio of their power and dispersive power
sum of the products of their power and dispersive power should be equal to zero
A wheel has a speed of 1200 revolution per minute and is made to slow down at a rate of 4 radian/sec2. The number of revolutions it makes before coming to rest is :
143
272
314
722
A circular coil of radius 11cm,carries and current of 2.5 amperes.If it has 700 turns,the flux density at the centre of the coil is
0.1mT
5mT
10mT
20mT
The focal length of a lens of dispersive power 0.45 which should be placed in contact with a convex lens of focal length 84 cm and dispersive power 0.21 to make the achromatic combination from the two lenses, in cm is
45
90
180
-180
Two electric charges 12 μC and -6 μC are placed 20 cm apart in air, there will be a point P at which electric potential is zero outside excluding the region between them. The distance of P from -6 μC charge is:
0.10 m
0.15 m
0.20 m
0.25 m
If a body is in equilibrium under a set of non-collinear forces, the minimum number of forces has to be
four
three
two
five
X-rays of energy 50 KeV are scattered from a carbon target. The scattered rays are detected at 900 from the incident beam. the percentage change in wave length approximately [mo=9.0x10-31kg, c=3x108 m/sec] is
10%
20%
5%
1%
A juggler maintains four balls on motion, making each inturn rise to a height 20m from his hand. Where will the other three balls be at the instant when the fourth one is just leaving the hand?
15m,20m,15m
10m,20m,10m
5m,15m,5m
4m,16m,4m
A oil drop having a mass 4.8 x10-10 g and charge 2.4 x 10-18 C stands still between two charged horizontal plates separated by a distance of 1 cm. If now the polarity of the plates is changed, instantaneous acceleration of the drop is : (g = 10 ms-2)
5 ms-2
10 ms-2
15 ms-2
20 ms-2
The speed of transverse vibrations in a stretched string is 700cm/s.If the string is 2m long,the frequency with which it resonates in fundamental mode is
7/3 Hz
7/4 Hz
14Hz
2/7 Hz
A man slides down on a telegraphic pole with an acceleration equal to one-fourth of acceleration due to gravity. The frictional force between man and pole is equal to in terms of man's weight w
w/4
w/2
3w/4
w
A potentiometer having a 4m long wire is connected to the terminals of a battery of constant output voltage. A Leclanche cell has a balancing length of 1m. If the length of the potentiometer wire is increased by 1m, then the position of the null point is
1.5m
1.25m
10.05m
1.31m
The dark lines in the solar spectrum are due to:
Absorption of certain wavelengths by elements present in the outer layer
Absence of certain elements in the sun
Black body radiation from the sun
Scattering of light
A segment of wire vibrates with a fundamental frequency of 450 Hz under a tension of 9 kg wt. Then tension at which the fundamental frequency of the same wire becomes 900 Hz is
36 kg-wt
27 kg-wt
18 kg-wt
72 kg-wt
Two solid spheres A and B made of the same material have radii rA and rB respectively. Both the spheres are cooled from the same temperature under the conditions valid for Newton's law of cooling. The ratio of the rate of change of temperature of A and B is :
rA/rB
rB/rA
r2A/ r2B
r2B/r2A
A particle is projected from the ground with an initial velocity of 20ms-1 at an angle of 300 with horizontal. The magnitude of change in velocity in 0.5 seconds is(g=10ms-1)
2ms-1
2.5ms-1
4ms-1
5ms-1
A motor car of mass 300 kg is moving with a velocity of 25 m/s, by applying brakes the car was brought to rest in a distance of 15 metres. The force of retardation in newton is :
2500
4500
6250
7500
An open pipe resonates to a frequency ‘f1’ and a closed pipe resonates to a frequency ‘f2’.If they are joined together to form a longer tube,then it will resonate to a frequency of(neglect end corrections)
f1f2/(2f2+f1)
f1f2/(f2+2f1)
2f1f2/(f2+f1)
(f1+2f2)/f2f1
The energy released by fission from 2g of 23592U in KWH is.(The energy released per fission is 200MeV).
2.27x104
4.54x104
4.54x106
2.27x106
A proton is projected with a velocity 107ms-1 ,at right angles to a uniform magnetic field of induction 100mT.The time(in seconds)taken by the proton to traverse 900 arc is:(Mass of proton=1.65x10-27kg and charge of proton = 1.6x10-19C
3.24x10-7
2.43 x10-7
1.62 x10-7
0.81 x10-7
Percentage of mass lost during the fission of 42U235 approximately is
0.01%
0.1%
0.7%
0.9%
If in a Wheatstone bridge the battery and Galvanometer are interchanged, the condition for balance
Is disturbed
Is not disturbed
Depends on the internal resistance of the bridge
Depends on the values of the resistances in the bridge.
A rectangular class room of volume 20×15×10 m3 has a surface whose average absorption coefficient is 0.035. When a material of area 1500m2 is brought into the room, the reverberation time falls to 2.5 seconds. The absorption coefficient of the material is nearly
0.12
0.28
0.36
A bullet of mass 10 g is fired horizontally with a velocity 1000ms-1 from a rifle situated at a height 50 m above the ground. If the bullet reaches the ground with a velocity 500ms-1, the work done against air resistance in the trajectory of the bullet is : (g=10ms-2)
5005J
3755J
3750J
17.5J
In two separate collisions, the coefficient of restitutions e1 and e2 are in the ratio 3:1. In the first collision the relative velocity of approach is twice the relative velocity of separation, then the ratio between relative velocity of approach and the relative velocity of separation in the second collision is
1 : 6
2 : 3
3 : 2
6 : 1
Under the application of force, a steel wire (Y = 19 x 1010Nm-2) of 5 m in length suffers an elongation of 1 mm. The potential energy stored per unit volume in this process, in joules per m3 is :
1.9 x103
9.5 x 103
3.8 x 103
The focal length of an equi-convex lens is greater than the radius of curvature of any of the surfaces. Then the refractive index of the material of the lens is :
greater than zero but less than 1.5
greater than 1.5 but less than 2.0
greater than 2.0 but less than 2.5
greater than 2.5 but less than 2.0
A motor of power P0 is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe n times, the power of the motor is increased to P1 The ratio of P1 to P0 is
n:1
n2 : 1
n3 : 1
n4 : 1
An n-p-n transistor power amplifier in C-E configuration gives :
voltage amplification only
currents amplification only
both current and voltage amplifications
only power gain of unity
Electrons ejected from the surface of a metal, when light of certain frequency is incident on it, are stopped fully by a retarding potential of 3 volts. Photoelectric effect in this metallic surface begins at a frequency 6 x 1014s-1. The frequency of the incident light in s-1is : [ Planck's constant = 6.4 x 10-34Js, charge on the electron = 1.6 x 10-19C]
7.5 x 1013
13.5 x 1013
13.5 x 1014
7.5 x 1015
A ray of light undergoes deviation of 300 when incident on an equilateral prism of refractive index√2.What is the angle of the ray inside the prism with the base of the prism?
00
Two cylindrical conductors A and B of same metallic material have their diameters in the ratio 1 : 2 and lengths in the ratio 2 : 1. If the temperature difference between their ends is same, the ratio of heats conducted respectively by A and B per sec is:
1 : 16
1 : 8
A rod with linear charge density λ is bent in the shape of circular ring.The electric potential at the centre of the circular ring is
2λ/ε0
λ/ε0
λ/2ε0
λ/4ε0
A quantity of heat Q is supplied to a mono atomic ideal gas which expands at constant pressure. The fraction of heat that goes into work done by the gas is :
2/5
3/5
2/3
1
An infinite number of charges each of magnitude q are placed on x-axis at distances of 1, 2, 4, 8, ….. meter from the origin. The intensity of the electric field at origin is
q/3π?0
q/6π?0
q/2π?0
q/4π?0
With a standard rectangular bar magnet of length (l), breadth (b; b < < l) and magnetic moment M, the time period of the magnet in a vibration magnetometer is 4 s. If the magnet is cut normal to its length into four equal pieces, the time period (in seconds) with one of the pieces is :
16
In a meterbridge experiment,the balance length is 40cm.the resistance in the gap opposite to this length of wire is 8 ohm.The resistance in the other gap is
10Ω
6Ω
4Ω
12Ω
A bucket filled with water is tied to a rope of length 0.5 m and is rotated in a circular path in vertical plane. The least velocity it should have at the lowest point of circle so that water doesnot spill is, (g = 10 ms-2 )
√5 m/s
√10 m/s
5 m/s
2√5 m/s
Two identical stringed instruments have a frequency of 100Hz.The tension in one of them is increased by 4%.If they are now sounded together the number of beats per second is
8
A pipe of length l1 closed at one end is kept in a chamber of gas of density ρ1.A second pipe open at both ends is placed in a second chamber of gas of density ρ2.The compressibility of both.The gases is equal.If frequency of first overtone in both the cases is equal,the length of the second pipe is
4/3 l1 √(ρ1/ρ2
4/3 l1 √(ρ2/ρ1
l1√(ρ2/ρ1
l1√(ρ1/ρ2
If two identical bar magnets, each of length l, pole strength m and magnetic moment M are placed perpendicular to each other with their unlike poles in contact, the magnetic moment of the combination is :
M / √2
lm ( √2 )
2 lm ( √2 )
2M
A steel wire can withstand a load up to 2940 N, A load of 150 kg, is suspended from a rigid support. The maximum angle through which the wire can be displaced from the mean position, so that the wire does not break when the load passes through the position of equilibrium, is
30o
60o
80o
85o
When two capacitors are joined in series the resultant capacity is 2.4 μF and when the same two are joined in parallel the resultant capacity is 10μF.their individual capacities are
7 μF,3μF
1μF,9μF
6μF,4μF
8μF,2μF
The radioactivity of a sample is 'X' at a time 't1' and ‘Y’ at a time 't2'. If the mean life time of the specimen is г the number of atoms that have disintegrated in the time interval (t1 – t2) is
Xt1 - Yt2
X-Y
X-Y / г
(X -Y) г
A double convex lens of focal length 30cm is made of glass of R.I.1.6. When it is immersed in a liquid, the focal length is found to be 90cm. The R.I of the liquid is
1.33
1.5
1.4
1.42
Identify the increasing order of the angular velocities of the following :1.earth rotating about its own axis2.hour's hand of a clock3.second's hand of a clock4.flywheel of radius 2 m making 300 rpm
1,2,3,4
2,3,4,1
3,4,1,2
4,1,2,3
In an experiment on photoelectric emission from a metallic surface, wavelength of incident light is 2xl0-7 m and stopping potential is 2.5 V. The threshold frequency of the metal (in Hz) approximately (charge of electron e= 1.6 x 10-19 C Planck's constant h = 6.67 x 10-34 J-s)
12 x 1015
9 x 1015
9 x 1014
12 x 1013
A 1.0 HP IP motor pumps out water from a well of 30m and fills water tank of volume 2238 litres at a height of 10 m from the ground. The running time of the motor to fill the empty water tank is: (g= 10 ms-2)
5 min
10 min
15 min
20 min
Thomson coefficient of a conductor is 10μVK. The two ends of it are kept at 500 C and 600 C respectively. Amount of heat absorbed by the conductor when a charge of 10 C flows through it, is:
1000 J
100 J
100 mJ
1 mJ
The radii and Young's moduli of two uniform wires A and B are in the ratio 2 : 1 and 1 : 2 respectively. Both wires are subjected to the same longitudinal force. If the increase in length of the wire A is one percent the percentage increase in length of the wire B is
1.0
2.0
3.0
Two bodies of 6 kg and 4 kg masses have their velocity 5i^-2j^+10k^ and 10i^-2j^+5k^ respectively. Then the velocity of their centre of mass is
5i ^+ 2j^ - 8k^
7i^ + 2j^ - 8k^
7i^ - 2j^+8k^
5i^-2j^+8k^
Consider the following statements A and B and identify the correct answer :(A) : In an elastic collision, if a body suffers a head on collision with another of same mass atrest, the first body comes to rest while the other starts moving with the velocity of the first one.(B) : Two bodies of equal mass suffering a head on elastic collision merely exchanges their velcities :
Both A and B are true
Both A and B are false
A is true but B is false
A is false but B is true
A current of 0.5A produes a deflection of 600 in tangent galvanometer. The current that produces a deflection of 300 in the same galvanometer is
0.5/√3A
0.5/√2A
0.5/3A
0.5/2A
A certain number of beats are heard when two tuning forks of natural frequencies n1 and n2 are sounded together. The number of beats heard when one of the forks is loaded :
increases
Decreases
Remains constant
may increase or decrease
Two cells A and B are connected in the secondary circuit of a potentiometer one at a time and the balancing length are respectively 400 cm and 440 cm. The emf of the cell A is 1.08 volt. The emf of the second cell B in volts is :
1.08
1.188
11.88
12.8
Two charges each of 100 micro coulomb are separated in a medium of relative permittivity 2 by a distance of 5cm.The force between them is
1.8x104N
1.8x104dyne
3.6x105N
0.36x105N