Download DWARKA INTERNATIONAL SCHOOL SECTOR

DWARKA INTERNATIONAL SCHOOL
SECTOR-12, DWARKA, NEW DELHI-78
PHYSICS
Sample paper
Class -XI
MAX MARKS: 70
TIME: 3 Hours
GENERAL INSTRUCTIONS:
1)
2)
3)
4)
5)
6)
All questions are compulsory.
Question numbers 1-8 are 1 mark questions.
Question numbers 9-18 are 2 marks questions.
Question numbers 19-27 are 3 marks questions.
Question numbers 28-30 are 5 mark questions.
There is no overall choice. However, internal choice has been provided in all the five marks questions. Only
one option in such questions is to be attempted.
W
1.
rite S.I unit of luminous intensity and temperature?
2.
I
fV=
at2
+
bt3
where V is in m/s and t is in seconds. What are the units of a and b?
3.
T
wo masses in the ratio 1:2 are thrown vertically up with the same speed. What is the effect on time
by the mass?
S
4.
hipra went from her home to school 2.5km away. On finding her home closed she returned to
her home immediately. What is her net displacement? What is the total distance covered by
her?
F
5.
riction is a self adjusting force. Justify.
W
6.
hat provides the centripetal force to a car taking a turn on a level road?
7.
A
spring is cut into two equal halves. How is the spring constant of each half affected?
8. What is work done in holding a 15kg suitcase while waiting for a bus for 15 minutes?
9.
I
f velocity, time and force were chosen the basic quantities, find the dimensions of mass?
10.
D
2
isplacement of a particle is given by the expression x = 3t + 7t – 9, where x is in meter and t is in
seconds. What is acceleration?
11.
A
balloon is ascending at the rate of 4.9m/s. A pocket is dropped from the balloon when situated at a
height of 245m. How long does it take the packet to reach the ground? What is its final velocity?
12.
W
hat is the angle between two forces of 2N and 3N having resultant as 4N?
W
13.
hat is the angle of projection at which horizontal range and maximum height are equal?
E
14.
xplain why, some leaves get detached when a tree is shaken vigorously?
G
15.
ive reason, why an atheist is made to land on sand or cushion?
W
16.
hy does a cyclist lean to one side, while going along curve?
A
17.
light body and a heavy body have same linear momentum. Which one has greater K.E.?
A
body of mass 3kg makes an elastic collision with another body at rest and continues to move in
the original direction with a speed equal to one – third of its original speed. Fine the mass of the
second body.
19.
T
he velocity V of water waves may depend on their wavelength, density of water and the
acceleration due to gravity. Find relation between these quantities by the method of dimension?
20.
A
stone is dropped from the top of a cliff and is found to ravel 44.1m diving the last second before
it reaches the ground. What is the height of the cliff? g = 9.8m/s2.
21.
E
18.
stablish s = ut + at2 from velocity time graph for a uniform accelerated motion?
22.
D
erive an equation for the path of a projectile fired parallel to horizontal.
23.
W
hat is meant by coefficient of friction and angel of friction? Establish the relation between the two?
24.
A
railway car of mass 20 tones moves with an initial speed of 54km/hr. On applying brakes, a constant
negative acceleration of 0.3m/s2 is produced.
(i) What is the breaking force acting on the car?
(ii) In what time it will stop?
(iii) What distance will be covered by the car before if finally stops?
25.
A
man weights 70 Kg. He stands on a weighting scale in a lift which is moving.
a)
U
pwards with a uniform speed of 10 m/s.
b)
D
2
ownwards with a uniform acceleration of 5 m/s .
c)
U
pwards with a uniform acceleration of 5 m/s2.
26.
D
erive the expression for the potential energy stored in a spring?
S
27.
how that for a freely falling body the sum of its kinetic energy and potential energy remains
constant at all points during its fall?
V
elocity time graph of a moving particle is shown. Find the displacement (a) 0 – 4 s (b) 0 – 8s (c)
0- 12 s from the graph. Also write the differences between distance and displacement.
Or
State and prove the triangle law of vector addition.
29.
D
erive an expression for acceleration of a body down a rough inclined plane.
OR
i.
E
xplain what is meant by coefficient of friction and angle of friction. Establish relation
between the two.
ii.
A
force of 49 N is just able to move a block of wood weighting 10 Kg on a rough horizontal
surface. Calculate the coefficient of friction and angle of friction.
30.
D
efine the kinetic and potential energy. Derive the expression of kinetic energy.
OR
Find the expression for the velocity of the two particles undergoing elastic collision in one
dimension.
28.