Questions for 19-10-2007

1.

Statement – 1

A block of mass m starts moving on a rough horizontal surface with a velocity v. It stops due to
friction between the block and surface after moving through a certain distance. The surface is
now tilted to an angle 30° with the horizontal and the same block is made to go up on the surface
with the same initial velocity v. The decrease in the mechanical energy in the second situation is
smaller than that in the first situation.
Because

Statement - 2
The coefficient of friction between the block and the surface decreases with the increase in the
angle of inclination.


(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

2.

STATEMENT.1: Glucose gives a reddish.brown precipitate with Fehling’s solution.

Because

STATEMENT.2: Reaction of glucose with Fehling’s solution gives CuO and gluconic acid.


(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.


3.

The differential equation dy/dx = [SQRT(1-y^2)]/y
determines a family of circles with

(A) variable radii and a fixed centre at (0, 1)
(B) variable radii and a fixed centre at (0, –1)
(C) fixed radius 1 and variable centres along the x-axis
(D) fixed radius 1 and variable centres along the y-axis