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Physics____
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1.
A ball A is thrown upfrom the edge of cliff and it lands
below on the ground. Another indentical ball B is thrown down from the cliff with
the same velocity as that of A. If the velocity of the ball A just before hitting
the ground is v_{A} and the velocity of B just before hitting the ground
is v_{B} then

(a)
**v**_{A} = v_{B}, (b) v_{A} > v_{B} (c) v_{A} < v_{B} (d) nothing can be said
about their velocities

2.
Water drips from the nozzle of a shower onto the floor 2m
below. The drops fall at regular intervals of time, the first drop striking the
floor at the instant the fourth drop begins to fall. What is the location of the
second drop from the floor? **8/9m**

3.
Three vectors
, and
are given. What is the value of 3C.(2A
X B)? **540**

4.
A person
walks up a stalled 20m long escalator in 120s. When standing on the moving escalator
he is carried up the same distance in 80 seconds. The
time required to walk up the moving escalator is

(a)
24s
(b) **
48s**
(c) 72s
(d) 96s

5.
A passenger
of mass 80Kg stands on the floor of an elevator. If the elevator moves up with an
acceleration 2m/s^{2} then the normal reaction of the floor of the elevator
on the man is (assume g=10m/s^{2}) is

(a)
800N
(b) 640N (c) **
960N** (d) 160N

6.
A 10Kg monkey climbs up a massless rope that runs over a
frictionless branch of a tree and back down to a 15Kg package on the ground. The
magnitude of the least acceleration the monkey must have if it is to lift the package
off the ground is

(a)
9.8m/s^{2}
(b) 19.6m/s^{2} (c) **
4.9m/s**^{2} (d) 2.45m/s^{2}

7.
A worker wishes to pile a cone of sand onto a circular area
of radius 2m. The coefficient of static coefficient of friction between each layer
of sand along the slope and the sand beneath it is 0.7 then assuming no slip the
greatest height that the pile of sand can have is

(a)
2m (b) **
1.4m** (c) 1m
(d) 0.7m

8.
A disc of mass 1kgslides along a circular path of radius
1m, on a frictionless table while attached
to a hanging block of mass 10kg through a hole in the table. The speed that can keep the block at rest is (assume
g = 10m/s^{2})

(a)
1m/s (b) 5m/s
(c) **10m/s**
(d) 20m/s

9.
A helicopter lifts a 70Kg diver from the sea by means of
a cable 50m long. The acceleration of the diver is g/20. How much work is done on
the diver by the force from the helicopter? (take g as 10m/s^{2}) **
1750J**

10. The
force on a particle is directed along the x-axis and given by F = 240[(x/5)^{2}
– 1]. The work done by the force in moving the particle from x = 0 to x = 20 is

(a)
18.8kJ
(b) 19.8kJ
(c) **20.8kJ**
(d)21.8kJ

11. A
50Kg bungee cord jumper is on a cliff 50m high above a stream. The elastic bungee
cord has a relaxed length of 40m. The feet of the bungee jumper stops 2m above the
stream. Assume that the cord obeys Hooke’s law the spring constant of the cord is
(assume g = 10m/s^{2})

(a)
250N/m
(b) 500N/m (c) **750N/m**
(d) 1000N/m

12. A 5kg block is dropped from
a height of 20cm onto a spring of force constant 2000N/m. The distance moved by
the block after coming in contact with the spring is

(a)
5cm (b) **
10cm** (c)15cm
(d)20cm

13. An
object is placed on top of a hemispherical mound of ice of radius 6m. The object
is given a small push after which it starts sliding. The height above the ground
when the object leaves the hemispherical
mound is

(a)
3m (b)
6m (c)
1m (d) **
4m**

14. A
4kg block is placed on a horizontal surface and is connected to a spring of force
constant 800N/m. The spring is compressed and then released. After the spring attains
the relaxed length the block travels over the surface for a distance 10m. If the
coefficient of kinetic friction for the surface is 0.4 the heat generated is

(a)
100J (b) 120J
(c)140J (d) **
160J**

15. The coordinates of three masses
1kg, 3kg and 6kg are (1,1), (3,3) and (6,6) respectively.
The coordinate of the centre of mass is

(a)
(2,2) (b)
(3,3) (c) (4,4)
(d) **(5,5)**

16. A
rod strikes a stationary ball with an average force of 50N over a time of 10ms.
If the ball has mass 0.2kg the speed of the ball after the impact is

(a)
**2.5m/s**
(b) 5m/s
(c) 10m/s
(d) 20m/s

17. The
angular position of a point on a rotating wheel is given by θ = 2t^{2}
+ 4t +4. The angular velocity of the
point at t = 16s is

(a)
60rad/s (b)64rad/s (c) **
68rad/s**
(d)72rad/s

18. A
wheel of radius R is placed against a step of height h. If the mass of the wheel
is 10kg then the horizontal force required to be applied to the axle to lift the
wheel over the step assuming R = 2h is (take g = 10m/s^{2})

(a)
**173N** (b)
273N (c)373N (d) 473N

19. Air
flows over the wing of an aircraft of area 50m^{2} with a speed 150m/s and
under the wing, also of the same area, with a speed 125m/s. If the density of air
is 1.25kg/m^{3} the upthrust on the wing is

(a)
0.415MN
(b) 0.315MN (c)
**0.215MN **
(d) 0.115MN

20. A
block of mass 5kg is attached to two identical springs on either side of it. The
springs are attached to the walls. The spring constant of the springs is 25N/m.
The frequency of oscillation of the mass, when displaced from the equilibrium, is

(a)
2Hz (b) 1Hz
(c) **0.5Hz**
(d) 0.25Hz

21. An
acoustic burglar alarm has a source emitting waves of frequency 100Hz. When a stranger
moves towards the alarm a beat frequency of 5Hz is detected. The speed of the stranger
is (assume speed of sound as 330m/s)

(a)
6.04Hz (b)
7.04Hz (c)
**8.04Hz**
(d)9.04Hz

22. 10
moles of an ideal gas expand adiabatically from an initial temperature 100K to a
final temperature 200K. If C_{V} is the molar specific heat capacity of
the gas at constant volume the work done by the gas is

(a)
10C_{V} (b)
100C_{V} (c) **
1000C**_{V}
(d) 10000C_{V}

23. The
motor in a refrigerator has a power of 240W. The freezing chamber is at 290K and
the outside air is at 320K. What is maximum amount of energy that can be extracted
in 30min assuming that the refrigerator works as a Carnot cycle in reverse? **
40500J**

24. Two
small conducting balls of mass 50g and carrying a charge 10microcoulomb hang from
a thread of length 50cm. The separation between the balls at any instant is (g =10m/s^{2})

(a)
**1.2m**
(b) 1m (c) 0.8m
(d) 0.6m

**25.
**A thin non conducting rod of length 1m has a charge
of 1C uniformly distributed over it. What is the electric field at a point on the
perpendicular bisector of the rod 0.5m from the centre? **
24.5 x 10**^{9}V/m

26. Charge
is distributed uniformly throughout the volume of an infinitely long cylinder of
radius R with a charge density ρ. The electric field at a distance r (<
R) cm from the axis of the cylinder is

(a)
**ρ r/2ε**_{0}
(b) ρ
r/ε_{0} (c) 2ρ
r/ε_{0} (d)
ρ rε_{0}

27. A
cylindrical capacitor has an internal radius r and external radius R. Half the stored
electrical energy lies within a cylinder of radius

(a)
R+ r (b)
**(rR)**^{0.5}
(c) (R -r)
(d) (rR)

28. A
wire L metres long is stretched to twice its length such
that there is no change in the volume of the wire. If the wire earlier had a resistance
R the new resistance of the wire is

(a)
R (b)
2R (c)
3R (d) **
4R**

29. When
a wire L metres long is turned into a circular coil the magnetic field at the centre
for a current I is B. The wire is wound into n turns. If the same current passes
through the coil what is the magnetic field at the centre of the coil? **
100B**

30. Two
long parallel wires of equal radius R are placed a distance r apart. If they carry
equal currents in opposite directions then the inductance per unit length of the
pair of wires is

(a)
**(μ**_{0}/π)(ln(r –
R)/r (b) (μ_{0}/π)(ln(r
+ R)/r (c) (μ_{0}π)(ln(r
– R)/r (d) (μ_{0}/π)(ln(r)/(r+R)

31. The
optical path length of a ray of light in vacuum is 2cm. The optical path length
in a medium of refractive index 2 is

(a)
1cm (b)
**4cm**
(c) 2cm (d) 0

32. A
source and a screen are a distance 10cm apart. If the focal length of the lens is
2cm then two real images are formed for lens position separated by

(a)
2.24cm
(b) **
4.48cm** (c) 6.72cm (d)
8.96cm

33. A
glass lens is coated on one side with a thin film of magnesium fluoride whose refractive
index is 1.38. if the refractive index of glass is 1.5 what is the least thickness
that eliminates reflections at 550nm

(a)
50nm (b) **
100nm** (c)150nm (d)200nm

34. The
wavelength associated with the cutoff frequency for a metal is 300nm. What is the
maximum kinetic energy of electrons ejected from the metal surface by UV light of
wavelength 250nm? **0.82eV**

35. A
1.00g sample of Samarium (Sm) emits alpha particles at a rate of
120 particles/s. The isotope responsible for the decay is Sm - 147
has a natural abundance in bulk samarium of 15%. The half life for
the decay process is

(a)
10^{9} y (b) 10^{10} y
(c) **
10**^{11} y
(d) 10^{12} y