PHYSICS
FOR JEE MAIN
______________________ __________________________________ ____________ _________
4) Two bars bars of masses masses 1) A student performs an experiment o
1 and m2 ,conn ,connected ected by a
weightless sp spring of of st stiffness k , rest on a smooth
dete determ rmin ine e the the You Young ng’s ’s modu modulu luss of of a wire ,exactly 2m long, long, by Searle’s Searle’s method method increase increase in the length of the wire wire to be 0.8mm 0.8mm with an uncertaint tainty y of
horizontal horizontal plane. Bar 2 is shifted by a small dist distan ancce x0 x0 to to th the le left and released. The velocity of the centre centre of mass mass of th the system when the bar 1
±0.0 ±0.05m 5mm m at at a loa load d of exac exactl tly y 1.0 1.0 kg. kg. T e student
breaks off the wall is
also measures diameter of wire to be .4mm with an uncertainity uncertainity of ±0.01mm. Take 2
g=9.8m/s (exact). (exact). The young’ young’ss modulu modulus obtained from the readind is: 11
2
b) (2.0±0.2) 10 N/m
2
d)(2.0±0.05) x 10 N/m
a)(2.0 a)(2.0 ±0.3) x 10 N/m 11
c) (2.0± 0.1)x10 0.1)x10 N/m
2) A bod body y is is pro proje ject cted ed at time time t =0 =0 fro fro
11
2
11
2
a)
b)
c)
d)
a certain
poin pointt on on a pla plane net’ t’ss sur surface face with with a cer certt in velocity at a certain angle with the planet’s sur face
5) Each pulley in figure has radius radius r and moment of
(ass (assum umed ed hori horizo zont ntal al). ). The The hori horizo zont ntal al and vertical
inertia I . The accelerati n of the block is
displaceme displacements nts x and and y respect respectively ively var vary with time t
= 10√ 3
in seconds as ,
= 10 −
(
and
. Th The maximum height attained by
a)
)
(
)
the body is
a)200m
b)100m c) c)50m d) d)25
( b)
)
(
)
3) A skier skier plans plans to ski ski a smooth smooth fixed fixed hemisphere
(
of radius R. He starts from rest from a curved smooth surface of heig eight R/4. /4. The anglle θ at whic which h
c)
he leaves the hemisphere is a) cos c) cos
b) cos d) cos
(
) (
d)
√ √
)
(
) )
6) If the radius of the earth decreases by 10 %, the
mass remaining unchanged, what will happen to the acceleration due to gravity? a) Decreases by 19% b) Increases by 19% c) Decreases by mo more t an 19% d) Inc Increas reases es by mor more th than 19%
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7) A steel wire 1.5m long and of radius 1mm is
10) A blo blocck of of mas masss M is connected to a spring of
atta attach ched ed wit with h a loa load d 3kg 3kg at at one one end end ,t e other end
force constant k and is laced on a horizontal
of the wire is fixed . it is whirled in a v rtical circle
surface. The block is displaced and it compresses
with with a freq freque uenc ncy y 2Hz. 2Hz. Find Find the the elon elonga gation of the
the spring by a. If a vertical wall is at a distance
wire when the weight is at the lowest position: ( Y
b(b
= 2 x 10
11
2
2
N/m , g=10m/s ) -3
-3
-7
-7
the the tim time e per perio iod d of of mot motiion of the block assuming elasti elasticc colli collisio sion n betwee betwee block and the wall
a)7.17 x 10 m b) 1.77 x 10 m
a)2
c)3.17 x 10 m d) 1.37 x 10 m 8) When at rest, a liquid stands at the same level
in the tubes tubes as shown shown in the the figure. figure. But as
c)
b)2
+ 4 s in
d)
+ sin
indicated, a height difference h occurs when the system is given an acceleration a towards the right. Then h is equal to a) b) 11)Thr Three rods rods of iden denti al cross-sectional area and
c)
-made from the same
d)
etal form the sides of an
isosceles isosceles triangle triangle ABC right angled at B as shown in 9) A glass rod rod of radius radius r1 is inserted symmetrically
the figure. The points A and B are maintained at
into a vert ertical capillary tube of radius r 2 such that
temperatures T and √ 2 T respectively in the
their lower ends are at the same level. The
steady state. Assuming that only heat conduction
arrangement is now dipped in water. he height to
take takess plac place, e, temp temper erat atu u e of point C will be
which water will rise into the tube will be(σ be(σ = surf surfac ace e ten tensi sion on of wat water er , =den =densi sity ty o water)
a)
(
b)
)
(
)
a)
√
b)
√
c)
(
)
d)
c)
√
d)
√ (√
)
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12) A therm hermo o dyna dynami miccal proc proces esss is shown in the -
3
figure with P A = 3 X Patm , V A A = 2 X 10 m , PB = 8 X -4
3
BC, Patm , V C C = 5 X 19=10 m . In the process AB & BC,
600 J and 200 J heat are added to the ystem. Find the the cha change nge in inte interrnal nal energ nergy y of the system in the 5
2
process CA. [ 1 Patm = 10 N/m ]
a)560 J
b)-560 J
c)-240 J
d)+240 J
15) Two fixed charges - Q and +Q are located at
points (-3a, 0) and (+3a, 0) respectively. Then which of the following statement is correct? a) points where the ele tric potential due to the two charges is zero in x – y plane, lie on a circle of radi radius us 4a and and cen centr tre e (5 (5 , 0) b) potential is zero at x = a and x = 9a c) both (a) and (b) are
rong
d) both (a) and (b) are c orrect
13) The given P – U graph shows the v riation of internal en energy of of an an id ideal ga gas wi with in increase in pressure. Which of the following press ur ure – volume graphs is equivalent to this gra ph?
16) A galvanometer of resistance esistance 50 Ω is connected connected to a batter battery y of 3 V alon alon with resistance of 2950Ω in series. A full scale de lection of 30 divisions is obtained in the galvanometer. In order to reduce this deflection to 20 divisions the resistance in series should be
a)4450Ω
b)5050Ω
c)5550Ω
d)6050Ω
17) In the circuit, the p tential difference across the the cap capac acit itor or is 10 V. Each resistance is of 3 Ω. The cell is is ideal. ideal. The The e.m.f of the cell is
a) 14 V b) 16 V c) 18 V 14) An orga organ n pip pipe e of of 3.9 3.9 π m lon long, g, ope open at both
ends is driven driven to third third harmon harmonic ic stand standii ng wave. If the amplitude amplitude of of pressure pressure oscillati oscillation on i 1 % of 5 2 mean atmospheric pressure [ p 0 = 10 N/m ]. the maximu maximum m displ displace acemen mentt of partic particle le fro from mean position position will will be [Given [Given velocity velocity of soun sound = 200 m/s 3 and density density of air = 1.3 kg/m kg/m ] a)2.5 cm
b) 5 cm
c) 1 cm
d) 2 cm
d) 24 V 18) A particle (mass m nd charge q) is at rest at
= 10 units and = −8 ̂ + 6 ̂ units is switched on
origin. An electric field magnetic field
in the region . Speed of the particle as function of its z-coordinate is a)
c)
b)
d)
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19) Circ Circul ular ar loop loop of a wir wire e and and a stra straig ig t wire carry
23) A plane monochro atic light wave falls
curr curren ents ts Ic and Ie res respec pective tively ly as sho sho n in the
norm normal ally ly on on a dia diaph phra rag g
figure. Assuming that these are placed in the same
sepa separrated ated by 2.5 2.5 mm. mm. The fringe pattern is formed
plane. The magnetic magnetic fields fields will be zer at the
on a screen 100 cm cm behind the diaphragm. By what
centre centre of the loop loop when when the the separat separatio io H is
dist distan ance ce will will thes these e fri fring nges be displaced, when one
with two narrow slits
of the the slit slitss is covered covered b a glass plate (µ=1.5) of a)
thickness thickness 10 µm ?
b)
c)
d)
20) In the given circuit containing an in ductor and
resi resist stor ors, s, the the tim time e cons consta tant nt of of the the circ circ it is a)
b)
c)
d)
b) 1 mm
c) 3 mm
d) 4 mm
24) When When an an alte alterna rnatin tin voltage of 220 V is applied across a devise P, a current of 0.25A flows through the circ circuit uit and and it it voltag voltag by an angle π/2 radian. radian. When the same voltage source is connected across another device Q, the ame current is observed in the circuit but in phase with the applied voltage. What What is the curre urrent nt wh n the same source is conn connec ecte ted d acr acros osss a ser seriies combination of P and Q ?
a)
21) A ray ray of ligh lightt mak makes es norm normal al inci incide de ce on the diagonal diagonal face face of a right right – angled angled prism prism as shown in 0 figure. If If = 37 37 then the angle of devi tion is (sin 0 37 = 3/5)
a)530
a) 2 mm
b)1270
c)1060
b)
c)
d)900
22) A cubi cubical cal block block of glass glass of refrac refracti ti e index n1 is in contact with the surface of water of refractive index n2. A beam of light is incident on vertical face on the block. After refraction a total in ternal reflection at the base and refraction at the oppo opposi site te fac face tak take e pla place ce.. The The ray ray em eme ges at angle as show shown. n. The The val value ue of is give given n by by
d)
√ √ √
A lagging in phase by π/4 with with voltag voltage e
A leading in ph se by π/4 with voltage voltage
A lagg laggin ing g in in pha phass by π/4 with voltage voltage
√
A lagging in ph se by π/2 with voltage voltage
25) Electrons in a hydrogen like atom (Z= 3) make
transitions from fourth excited state to third excited state and from hird to second excited state. The resulting radiations are incident on a metal plate to eject ph toelectrons. The stopping
a) sin b) cos
< <
− −
potential for photoelec rons ejected by the shorter wave wavellengt ength h is is 3.9 3.95 5 V. V. T e stopping potential for the ph photoelect ectrons ons ej ejected by the longer wavelength is
c) sin
<
a) 2.0 V
b)0.75 V
c) 0.6 V
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26) A radioactive nuclide is produced t the
29) 1 kW signal is trans itted using a
constant rate of n per second ( say, by bombarding
communica communication tion channe channel which provides
a target with neutrons). The expected number N of
attenuation at the rate of -2dB -2dB per km. km. If the
nuclei in existence t s after after the numbe number is N0 is
communica communication tion channe channel has a focal length of 5km,
given by
the power of the signal received is:
a) N = N0 c) N =
b) N = +
+ (N0 -
)
( gain in dB = 10
0
d) N = + (N0 +
)
log
)
a) 900 900 W b) 100W 100W c) 990 W d) 1010 W
27) An X-ray tube is operat operating ing at at 150 kV and 10
mA. If only 1% of the electric power supplied is conv conver erte ted d into into X – rays rays,, the the rate rate at which the target is heated in calorie per second i s a) 3.55
b)35.5
c) 355
30) The ratio of contrib tions made by the electric
and magnetic field component to the intensity of an EM wave is
d)3550
a) c :1 2
b) c : 1 28) A 220V A.C supply is connected between points
A and B . What will be the potential difference V across the capacitor? a) 220V c) 0V
b) 110V d) 220 √ 2 V
c) 1 : 1 d)√ : 1
