## Tuesday, February 2, 2010

### Topics Asked in IIT JEE 2009 Examination in Physics - Paper I

Specific Topic Asked in IIT JEE 2009 Examination in Physics - Paper I

1. Static coefficient of friction and inclined plane.

A block of base 10 cm × 10 cm and height 15 cm is kept on an inclined plane. The
coefficient of friction between them is square root of 3 . The inclination θ of this inclined plane from
the horizontal plane is gradually increased from 0º. Then
(A) at θ = 30º, the block will start sliding down the plane
(B) the block will remain at rest on the plane up to certain θ and then it will topple
(C) at θ = 60º, the block will start sliding down the plane and continue to do so at higher
angles
(D) at θ = 60º, the block will start sliding down the plane and on further increasing θ, it
will topple at certain θ

2. Simple harmonic motion graph and acceleration of the particle at an instant in time.

3. Spherical shell, Electric Charges and Charge densities

4. Electric flux on a specified surface due to multiple charges of various types: Point, wire, disc,

5. A system of bodies of different shapes with specified masses: Finding the centre of mass of system of bodies.

6. Wire body or frame in a magnetic field. Direction of current and amount of current to be specified.

7. Problem of apparent speed when somebody watches from under the water above.

8. Collisions between particles on a circular path.

9. Current and voltage in electric circuit of resistors.

10. Question on inertial frame

If the resultant of all the external forces acting on a system of particles is zero, then from
an inertial frame, one can surely say that
(A) linear momentum of the system does not change in time
(B) kinetic energy of the system does not change in time
(C) angular momentum of the system does not change in time
(D) potential energy of the system does not change in time

11. Errors in measurements

A student performed the experiment of determination of focal length of a concave mirror
by u-v method using an optical bench of length 1.5 meter. The focal length of the mirror
used is 24 cm. The maximum error in the location of the image can be 0.2 cm. The 5 sets
of (u, v) values recorded by the student (in cm) are : (42, 56), (48, 48), (60, 40), (66, 33),
(78, 39). The data set(s) that cannot come from experiment and is(are) incorrectly
recorded, is (are)
(A) (42, 56) (B) (48, 48) (C) (66, 33) (D) (78, 39)

12. Cv and Cp, the molar specific heat capacities of a gas at constant volume and
constant pressure for monoatomic gas and diatomic gas

(A) Cp – Cv is larger for a diatomic ideal gas than for a monoatomic ideal gas
(B) Cp + Cv is larger for a diatomic ideal gas than for a monoatomic ideal gas
(C) Cp / Cv is larger for a diatomic ideal gas than for a monoatomic ideal gas
(D) Cp . Cv is larger for a diatomic ideal gas than for a monoatomic ideal gas