## Sunday, October 11, 2009

### IIT JEE Physics Final Revision Set 9

1. A long, hollow conducting cylinder is
kept coaxially inside another long,
hollow conducting cylinder of longer
radius. Both the cylinders are initially
electrically neutral.

a. A potential difference appears between
the two cylinders when a charge density
to the inner cylinder.
b. A potential difference appears between
the two cylinders when a charge density
is given to the outer cylinder.
c. No potential difference appears
between the two cylinders when a
uniform line charge is kept along the
axis of the cylinders.
d. No potential difference appears
between the two cylinders when same
charge density is given to both the
cylinders.

2. In an experiment to determine the focal
length (f) of a concave mirror by the u-v
method, a student places the object pin
A on the principal axis at a distance x
from the pole P. The student looks at the
pin and its inverted image from a
distance keeping his/her eye in line with
PA. When the student shifts his/her eye
towards left, the image appears to the
right of the object pin. Then,

a. x is l.t. f b. f is l.t. x is l.t. 2f
c. x = 2f d. x > 2f

3.The largest wavelength in the ultraviolet
region of the hydrogen spectrum is 122
nm. The smallest wavelength in the
infrared region of the hydrogen spectrum
(to the nearest integer) is
a. 802 nm b. 823 nm
c. 1882 nm d. 1648 nm

4. A resistance of 2Ω is connected across
one gap of a metre-bridge (the length of
the wire is 100 cm) and an unknown
resistance, greater than 2Ω , is
connected across the other gap. When
these resistance are interchanged, the
balance point shifts by 20 cm. Neglecting
any corrections, the unknown resistance
is
a. 3Ω b. 4Ω
c. 5Ω d. 6Ω

5. A ray of light traveling in water is
incident on its surface open to air. The
angle of incidence is θ, which is less
than the critical angle. Then there will be
1. Only a reflected ray and no refracted
ray
2. Only a refracted ray and no reflected
ray
3. A reflected ray and a refracted ray and
the angle between them would be less
than 180° – 2θ
4. A reflected ray and a refracted ray and
the angle between them would be greater
than
180° – 2θ .

Source 2007 Paper 1