## Monday, October 12, 2009

### IIT JEE Physics Final Revision Set 34

1. STATEMENT-1
For an observer looking out through the window of a fast moving train, the nearby objects appear to move
in the opposite direction to the train, while the distant object appear to be stationary.

and
STATEMENT-2
If the observer and the object are moving at velocities V1 and V2 respectively with reference to a laboratory frame, the velocity of the object with respect to the observer is V2-V1.

(A) STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for
STATEMENT-1
(B) STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for
STATEMENT-1
(C) STATEMENT-1 is True, STATEMENT-2 is False
(D) STATEMENT-1 is False, STATEMENT-2 is True.

(Source: 2008 JEE paper 2)

2. The term that correct for the attractive forces present in a real gas in the van der Waals equation is -
(A) nb (B)an²/V²

(C)-an²/V² (D) – nb

3. 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 √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

4. Three concentric metallic spherical shells of radii R, 2R, 3R are given charges Q1, Q2, Q3 respectively. It is found that the surface charge densities on the outer surfaces of the shells are equal. Then, the ratio of the charges given to the shells, Q1 : Q2 : Q3 is-

(A) 1 : 2 : 3 (B) 1 : 3 : 5 (C) 1 : 4 : 9 (D) 1 : 8 : 18

5. A ball is dropped from a height of 20 m above the surface of water in a lake. The
refractive index of water is 4/3. A fish inside the lake, in the line of fall of the ball, is
looking at the ball. At an instant, when the ball is 12.8 m above the water surface, the
fish sees the speed of ball as-
(A) 9 m/s (B) 12 m/s (C) 16 m/s (D) 21.33 m/s

Source: JEE 2009 paper 1