BITSAT – Grand Test - 2

Transcription

BITSAT – Grand Test - 2
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BITSAT – Grand Test - 2
1. If the dimensions of velocity, acceleration and length are yz–1, yz–2 and xy
respectively, the dimensions of the coefficient of friction is
1) x0y0z0
3) x1y0z0
4) x–1y–1z0
If a uniform rod with electrical resistivity ‘s’, mass m, specific heat C, length L,
co
m
2.
2) x–1y0z0
corss sectional are A and coefficient of linear expansion α is connected across a
battery of emf E, then increase in length of this rod in a small time internal t is
AE 2 tα
sm
2)
AE 2 tα
smCL
AE 2 tα
smC
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1)
3)
4)
AE 2 tαL
sm
3.In the circuit, shown in fig. ‘K’ is open. The charge on capacitor C in steady state is q1.
Now key is closed and at steady state, the charge on C is q2. The ratio of charges
is
K
R
C
⎞
⎟⎟
⎠
2R
3
2
2)
.s
a
1)
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E
⎛ q1
⎜⎜
⎝ q2
2
3
3)
1
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4.At a given place where acceleration due to gravity is ‘g’
density ‘d’
kg / m 3
4)
m / sec 2
is gently released in a column of liquid of density
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sphere will
1) Fall vertically with an acceleration ‘g’
m / sec 2
2) Fall vertically with no acceleration
3) Fall vertically with an acceleration
⎛d−ρ⎞
g⎜
⎟
⎝ d ⎠
4) Fall vertically with an acceleration
⎛ρ⎞
g⎜ ⎟
⎝d⎠
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1
2
, a sphere of lead of
' ρ ' kg / m 3 .
If
d>ρ,
the
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5.A drop of water breaks into two droplets of equal size. In this process, which of the
following statement is correct
1) The sum of temperature of the two droplets together is
equal to the original temperature of the drop
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2) The sum of masses of the two droplets is equal to the original mass of the drop
3) The sum of the radii of two droplets is equal to the radius of the original drop
4) The sum of the surface areas of the two droplets is equal to the surface area of the
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original drop
6.Two particles execute S.H.M. of same amplitude and frequency along the same straight
line. They pass one another when going in opposite directions, and each time their
displacement is half of their amplitude. The phase difference between them is
2) 60°
3) 90°
4) 120°
Two point charges 2q and 8q are placed at a distance r apart. Where should a third
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7.
1) 30°
charge – q be placed between them so that the electrical potential energy of the
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system is a minimum
.s
a
1) at a distance of r/3 from 2q
3) at a distance of r/16 from 2q
4) there is no such position
An inductance ‘L’ and capacitance ‘C’ and resistance R are connected in series
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8.
2) at a distance of 2r/3 from 2q
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across an AC source of angular frequency ‘ω’. If
ω2 >
1
then
LC
1) emf leads the current
2) both the emf and the current are in phase
3) current leads the emf
4) emf lags behind the current
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9.
A straight conductor AB of length 1 m is held horizontally at a certain height in the
East - West direction (A is towards East) and is allowed to fall freely. The emf
induced between its ends at the instant 2s after dropping it is ( B H = 4 × 10 −5 T , g =
10ms −2 )
3) 0.8 mV and B is at higher potential
2) 0.4 mV and B is at higher potential
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1) 0.4 mV and A is at higher potential
4) 0.8 mV and A is at higher potential
10. When a resistance of 9.5Ω is connected across a battery, the voltage across the
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resistance is 11.4V. If the resistance connected across the same battery is 11.5Ω,
the voltage across the resistance is 11.5V, then
1) The emf of the battery is 12 V
2) The emf of the battery is 13.5 V
3) The internal resistance of the battery is 1 Ω
4) The internal resistance of the battery is 0.5 Ω
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11.A gas undergoes a change of state during which 100 J of heat is supplied to it and it
does 20 J of work. The system is brought back to its original state through a process
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during which 20 J of heat is released by the gas. The work done by the gas in the second
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process is
3)
80 J
4)
20 J
In two separate collisions, the coefficient of restitutions e1 and e2 are in the ratio
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12
2) 40 J
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1) 60 J
3:1. In the first collision the relative velocity of approach is twice the relative
velocity of separation, and then the ratio between relative velocity of approach and
the relative velocity of separation in the second collision is
1) 1:6
2) 2:3
3) 3:2
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4) 6:1
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13. A body thrown vertically upwards with an initial velocity
u
reaches maximum
height in 6 seconds. The ratio of the distances travelled by the body in the first
second and the seventh second is
2) 11 : 1
3) 1 : 2
4)1 : 11
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1) 1 : 1
14. Arrange the following vectors in the increasing order for their orientation with the x-
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axis
(c) iˆ + ˆj
(a) iˆ + 2 ˆj
(b) 5iˆ
1) a,b,d,c
2) c,a,b,d
2iˆ + ˆj
(d)
3) d,c,b,d
4) b,d,c,a
15.Time period of revolution of a nearest satellite around a planet of radius R is T. Period
of revolution around another planet, whose radius is 3R but having same density is
1) T
2) 3T
3) 9T
4)
3 3T
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16.A large tank filled with water to a height ‘h’ is to be emptied through a small hole at
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the bottom. The ratio of time taken for the level of water to fall from h to
1)
2
.s
a
to zero is
2)
1
3)
2
2 −1
4)
h
2
and from
h
2
1
2 −1
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17. A uniform rod of length 60 cm and mass 6kg is acted upon by two forces as shown
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in the diagram. The force exerted by 45 cm part ofthe rod on 15 cm part of the rod is
1) 10 N
21N
15cm
2) 17 N
45cm
45N
3) 27 N
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4) 24 N
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18. A body slides down a smooth inclined plane of height h and angle of
inclination 30º reaching the bottom with a velocity v. Without changing the height,
if the angle of inclination is doubled, the velocity with which it reaches the
bottom of the plane is
1. v
2. v/2
3. 2v
4.
normal to
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19. A) When two spheres collide momentum transfer takes place along
2v
tangent drawn at contact surface
B) When a ball hits a wall at an angle to horizontal its momentum along the wall
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remain constant
C) When a ball bounces ‘n’ times before coming to rest the total time elapsed is
2h 1 + e
g 1− e
t=
1) A,B are true
2) A,C are false
3) A,B,C are true
4) A,B,C are false
20.Two wires A and B of same length, same area of cross-section having the same
Young's modulus are heated to the same range of temperature. If the coefficient of linear
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expansion of A is 3/2 times of that of wire B. The ratio of the forces produced in two
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wires will be
1) 2/3
2) 9/4
In a compound microscope, the image formed by the objective is
1) Virtual, erect and magnified
2) real, erect and magnified
3) Real, inverted magnified
4) virtual, erect and diminished
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4) 3/2
.s
a
3) 4/9
22.
In photo electric Experiment, the stopping potential for a given metal is ‘V’ volt
when radiation of wavelength λ is used. If radiation of wavelength 2λ is used with
same metal, then stopping potential in volt is
1) 2V +
hc
eλ
2) V +
hc
eλ
3) V +
hc
2eλ
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4) V −
hc
2eλ
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23.
In Fraunhoffer diffraction
1) The diffraction effect in the direction of the propagation of light only is studied
2) The source and the screen are at infinite distances
4) No lenses are required
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3) The wave fronts are spherical
If λ1 and λ2 denote the wavelengths of de-Brgle waves for electrons in the first and
24.
1) 2:1
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second Bohr orbits in hydrogen atom then λ1:λ2 is equal to
2) 1:2
3) 1:4
4) 4:1
25. A dog weighing 5 kg is standing on a flat boat so that it is 10 meters from the shore.
It walks 4 m on the boat toward the shore and then halts. The boat weighs 20 kg and
one can assume that there is no friction between it and water. How far is the dog from
the shore at the end of this time?
1)12 m
2) 1.8 m
3) 6.8 m
4) 3.2 m
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26. A body of mass m is thrown upwards at an angle θ with the horizontal with velocity
v 2 + g 2t 2 − (2 v sin θ ) gt
2)
(v cos θ − v sin θ ) 2 − gt
4)
v 2 + g 2t 2 − (2 v cos θ ) gt
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3)
(v cos θ ) 2 + (v sin θ ) 2
.s
a
1)
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v. While rising up the velocity of the mass after t seconds will be
27. A balloon of mass M is stationary in air. It has a ladder on which a man of mass m is
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standing. If the man starts climbing up the ladder with a velocity v relative to ladder,
the velocity of balloon is
1)
m
v Upwards
M
3)
mv
Upwards
(M + m)
2)
4)
mv
downwards
(M + m)
Mv
Downwards
(M + m)
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28. A uniform chain of mass 'm' and length 'L' is kept on a horizontal table with half of its
length hanging from the edge of the table. Work done in pulling the chain on to the
table so that only
1
th of its length now hangs from the edge is,
5
mgl
8
mgl
50
2)
29. A sphere of mass
m
3)
mgl
18
4)
21mgl
200
co
m
1)
is tied to end of a string of length l and rotated through the other
along a horizontal circular path with speed v . The work done in full horizontal
end
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circle is
⎛ mv 2 ⎞
1) 0
2) ⎜
⎟ .2π l
⎝ l ⎠
3) mg .2π l
⎛ mv 2 ⎞
4) ⎜
⎟ .(l )
⎝ l ⎠
30. A thin rod of mass m and length 2l is made to rotate about an axis passing through
its centre and perpendicular to it. If it angular velocity changes from 0 to ω in time
t, the torque acting on it is
ml 2ω
3t
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ml 2ω
12t
2)
3)
ml 2ω
t
4)
4ml 2ω
3t
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1)
31. A body of mass m kg. starts falling from a point 2R above the Earth’s surface. Its
.s
a
kinetic energy when it has fallen to a point ‘R’ above the Earth’s surface [R-Radius
of Earth, M-Mass of Earth, G-Gravitational Constant]
1 GMm
2 R
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1)
3)
2 GMm
3 R
2)
1 GMm
6 R
4)
1 GMm
3 R
32.A nucleus ZXA emits 9α-particles and 5p particle. The ratio of total protons and
neutrons in the final nucleus is
1)
Z − 13
( A − Z − 23 )
2)
(Z − 18 )
( A − 36 )
3)
(Z − 13 )
( A − 36 )
4)
(Z − 13 )
( A − Z − 13 )
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33. A liquid is kept in a cylindrical vessel which is being rotated about a vertical axis
through the centre of the circular base. If the radius of the vessel is r and angular
velocity of rotation is ω , then the difference in the heights of the liquid at the
centre of the vessel and the edge is
2 grω
3)
ω2
4)
2gr 2
The rectangular surface of area 8 cm x 4 cm of a black body at temperature 1270 C
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34.
r 2ω 2
2g
2)
co
m
rω
2g
1)
emits energy E per second. If length and breadth are reduced to half of the initial
value and the temperature is raised to 3270 C, the rate of emission of energy
becomes
3
E
8
1)
35.
2)
81
E
16
3)
9
E
16
4)
81
E
64
Two identical metal spheres carrying charges +2Q and -6Q separated by a certain
distance attract each other with a force F. If they are touched and kept at double
32 F
9
2) repulsive force of
9F
32
F
32
4) repulsive force of
F
12
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1) Attractive force of
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separation, then the force between them becomes
.s
a
3) Attractive force of
36. A square frame of side L carries a current i and the field at the centre of the frame is
The square frame is recast into a circular loop of radius R. When same current i
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B1.
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is passed through the circular loop, the magnetic field at it's centre is
B1
B2
1)
B2.
The ratio
is
8
π
2
2)
8 2
π
2
3)
16
π
2
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4)
8
2
π2
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A ray of light incident on an optical fiber where μcladding =1.4 and μcore =1.6 . The
37.
length of the fiber is 2.1km. The time taken by the light ray to come out of the fiber
, if the light ray is incident at an angle just greater than the critical angle at core –
cladding interface
2) 10.8μ s
3) 2.8μ s
4) 1.28μ s
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1) 12.8μ s
38. Highest frequency waves are:
2) Microwaves
2) infrared rays
3) ultraviolet rays
4) none of these
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39 . A particle of placed at the highest point of a frictionless hemispherical surface. If the
particle is allowed to slide down, the angular displacement θ at which it will leave
the surface is
⎛1⎞
⎛1⎞
1) cos −1 ⎜ ⎟
⎝ 3⎠
40.
⎛2⎞
2) cos −1 ⎜ ⎟
⎝2⎠
3) cos −1 ⎜ ⎟
⎝3⎠
⎛3⎞
4) cos −1 ⎜ ⎟
⎝4⎠
A vertical circular loop of wire of radius 9.42 cm is placed with its plane in the
magnetic meridian and a short magnetic needle is pivoted at the center of the loop
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so that can freely rotate in the horizontal plane. If a current of 6A is passed
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through the loop, then the needle gets a deflection of (BH = 4 x 10 –5 T)
1) 900
2) 450
4) Does not deflect
.s
a
3) Continuously rotates about the pivot.
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1
2
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1
3
3
1
4
3
5
2
6
4
7
4
8
1
9
4
10 2
11 1
12 4
13 2
14 4
15 1
16 4
17 3
18 1
19 3
20 4`
21 3
22 4
23 2
24 2
25 2
26 3
27 2
28 2
29 1
30 2
31 2
32 1
33 2
34 4
35 4
36 2
37 1
38 3
39 3
40 2
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