March 2011 - Career Point

5. A hollow conducting sphere is kept concentrically
f x
f d
2
− x
inside another hollow conducting sphere of larger (A) .
(B) .
radius. Three switches S 1 ,
2m 2 2
d − x
2m x
q 0
S 2 , S 3 are attach to system q 0
as shown. Initially charge
S
2 2
2 2
at each sphere is q 0 and all 3 S 1 S 2 f d d − x
f d d − x
(C) .
(D) .
2 2
2
switches are opened . Then
2m (2d − x ) 2m x
the potential difference
between the two sphere
SECTION – II
have non-zero value when–
Multiple Correct Answers Type
(A) S 1 and S 3 opened, S 2 closed
Questions 9 to 13 are multiple choice questions. Each
(B) S 1 and S 2 opened, S 3 closed
question has four choices (A), (B), (C) and (D), out of
(C) S 2 opened, S 1 and S 3 closed
which MULTIPLE (ONE OR MORE) is correct. Mark
(D) All S 1 , S 2 and S 3 closed
your response in OMR sheet against the question
6.
number of that question. + 3 marks will be given for
Consider a neutral conducting sphere with a non
each correct answer and no negative marks.
uniform cavity. A positive point charge and a
negative point charge are placed respectively at
centre of the sphere and outside the sphere. Then net
charge on the sphere is then (magnitude of charge is
9. One fourth part of an equiconvex lens of focal length
100 cm is removed as shown in the figure. An object
of height 1 cm is placed in
same for both charge)
front of the lens. It is
observed that all the images O
+q – q
are of equal height.then
400
(A) Object is at distance of cm from the lens.
(A) Negative and distributed uniform over the
3
surface of the sphere
(B) The magnitude of magnification produced by
(B) Negative and appears only at the point on the
upper and lower part is equal
sphere closest to the point charge
(C) The number of image formed is two
(C) Negative and distributed non uniformly over the (D) The product of magnification of both the lenses
entire surface of the sphere
is negative
(D) zero
10. When photons of energy 4.25 eV strike the surface of
a metal A, the ejected photoelectrons have maximum
7. In an experiment to determine the focal length (f) of kinetic energy T A eV and de Broglie wavelength λ A .
a concave mirror by the u-v method, a student place The maximum kinetic energy of photoelectrons
the object pin A on the principle axis at a distance x liberated from another metal B by photons of energy
from the pole P. The student looks at the pin and its 4.70 eV is T B = (T A –1.50) eV. If the de broglie
inverted image from a distance keeping his/her eye in wavelength of these photoelectrons is λ B = 2λ A , then
line with PA. When the student shifts his/her eye (A) the work function of A is 1.25 eV
towards left the image appears to left of the object (B) the work function of B is 4.20 eV
pin. Then
(C) T A = 3.00 eV
(A) x < f
(B) f < x < 2f
(D) T B = 1.5 eV
(C) x = 2f
(D) x > 2f
11. In a RLC series circuit shown, the reading of
8. Two particles of mass m and particle of mass 2m are voltmeters V 1 and V 2
V 2
tied from a light string of length 2a. Both of mass m are 100V and 120V, R
tied at the ends of string and third particle tied at respectively. The
middle of string. The whole system is kept on a source voltage is
V 1
frictionless horizontal surface with the string held 130V. For this
tight so that each mass is at a distance 'd' from the situation mark out the
V
center p(as shown in figure). Now the particle at mid correct statement (s).
point of the string is pulled
horizontally with a small but
constant force 'f '. As a result the
particles at end of string move
towards each other on the surface.
The magnitude of acceleration,
when the separation between them
becomes 2x is–
m
d
f
P
2m
d
m
(A) Voltage across resistor, inductor and capacitor
are 50 V, 86.6 V and 206.6 V,
(B) Voltage across resistor, inductor and capacitor
are 10V, 90V and 30V, respectively.
(C) Power factor of the circuit is 13
5
(D) Circuit is capacitive in nature
XtraEdge for IIT-JEE 56
MARCH 2011