Download Mongar Higher Secondary School

Mongar Higher Secondary School
Monger: Bhutan
Mid-term examination -2010
Time: 31/4hrs
Mark: 100
Sub: Physic
Class:
XI
Question 1
[10x1]
Choose the correct answer and write it in your answer sheet.
i)
The work done on the body is negative when the angle between force and
displacement is
a) 1800
b) 900
c) -900
d) -1800
ii)
The dimensional formula of pressure is
l
l
2
a)
b)
c)
d)
M
M
M
M
a)
b)
c)
d)
How many grams are there in one teragram?
1015
1012
10-12
1011
a)
b)
c)
d)
Vectors situated in one plane, irrespective of their directions are known as
Co-linear vectors
Co-initial vectors
Co-planar vectors
Polar vectors
a)
b)
c)
d)
The number of significant figures in 3400 is
4
3
1
2
iii)
iv)
v)
Class XI Phy.
2
1
1
LT
L T
L T
LT
2
0
1
2
2
1
Page 1 of 6
MHSS. Mid-Term Exam-2010
vi)
a)
b)
c)
d)
vii)
a)
b)
c)
d)
Newton’s second law gives the measure of
acceleration
force
momentum
impulse
gravitational unit of work in C.G. S system is
gcm
dyne cm
gmwt
gcms-1
viii) Two bodies, one light and other heavy have equal kinetic energies. Which of
them has greater momentum?
a) Both have same momenta
b) The heavy body
c) The lighter body
d) None of the above
ix)
a)
b)
c)
d)
Name the quantity which is a vector
Distance
Speed
Pressure
Acceleration
a)
b)
c)
d)
A body moves along a straight line, the motion of the body is said to be
Three dimensional
One dimensional
Two dimensional
None of the above
x)
Question 2
[5x1]
Fill in the blanks with the most appropriate word/words
a) Every system in equilibrium tends to exist in the state of
……………….potential energy
b) Forces which have null vector as a resultant are known as ……………..forces
c) Negative vector of the resultant of a number of vectors is called………….
d) RADAR stands for……………….
e) The value of co-efficient of restitution for perfectly inelastic collision
is……………….
Class XI Phy.
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MHSS. Mid-Term Exam-2010
Question 3
[5x1]
Write true of false for the statement below.
a) Newton’s 2nd law can be derived form 1st law and 3rd law can be derived from
1st law.
b) All zeros lying in between a decimal point and the first non-zero digit on its
right side are not significant
c) Principle of homogeneity states that the dimensional formula of every term on
the two sides of a correct relation must be same.
d) Cross product of two perpendicular vectors in always zero
e) Unit of impulse is same as the unit of momentum.
Question 4
[10x1]
Match the items of column A with the items in column B. Rewrite the correct
pairs in your answer sheet.
Column A

Column B
a) Scalar quantity

i) i  k
ii) Central force
iii) i.j
b) M1L1T-2

c)  j
d) Recoil of gun
iv) Acceleration
v) A.B

e) ABsinθ n
vi) Theory of Relativity
M 
v2
1 2
c

vii) Conservation of momentum
g) AB Cosθ n
h) force of friction
i) 0
j) Vector quantity
viii) mass
ix) Stress

m0

x) A x B

k) j
l) M1L-1T-2
m) Gravitational force
Class XI Phy.
Page 3 of 6
MHSS. Mid-Term Exam-2010
Question 5
Answer all questions
a) What is an electron volt? How is it related to joule?
b) Differentiate position vector and displacement vector?
[10x1]
o
c) Do the notations
A and AU stand for the same unit? Explain.
 
d) Show that P = F .V
e) State the rule governing the directions of cross product.
f) Explain why a tea cup breaks on falling on the ground?
g) A 1000kg vehicle is moving with a velocity of 10ms-1. calculate the magnitude
of the force which can increase its velocity to 25cm-1 in 5s
h) Define momentum and list the factors on which the momentum of the body
depends?
i) Define conservative force.
j) Write the dimensional formula of kinetic energy.
Part II. [60]
Answer any six questions.
Question 1
a) Explain why it is easier to pull than to push.
[4]
-2
-2
b) Convert an acceleration of 20ms into kmh .
[2]
c) State the parallelogram’s law of vectors.
[2]
d) Find the unit of length, mass and time if the unit of force, velocity and energy,
respectively are 100N, 10ms-1 and 500J.
[2]
Question 2
a) State Newton’s second law of motion. Derive Newton’s second law in


mathematical form as F  m a
b) Obtain the relationship between
i)
milligram and nanogram
ii)
petameter and micrometer.
[4]
[2]






c) Are the two vectors represented by 2 i  4 j  2 k and l  2 j  5 k perpendicular to
each other?
[2]
d) Write two limitations of dimensional analysis.
[2]
Class XI Phy.
Page 4 of 6
MHSS. Mid-Term Exam-2010
Question 3
a) Obtain the formula for apparent weight for a man in a lift when
i)
the lift possesses zero acceleration (a=0)
ii)
the lift moving upward with acceleration a.
iii) the lift moving downward with acceleration a
iv) the lift falling freely under gravity.
b) Check the correctness of the given relation. n 



1
2l
T
M

[4]
[2]


c) Find the angle between two vectors l  2 j  5 k and 2 i  j  4 k
d) Differentiate constant errors and random errors?
[2]
[2]
Question 4
a) Draw the graph of kinetic energy, potential energy and mechanical energy of a
freely falling body. What can you conclude from the graph?
[4]
b) An areoplane is flaying due north with a velocity of 90 km/hr. If the wind be
blowing from east with a velocity of 15km/hr, find the resultant velocity of the
areoplane.
[2]
c) Define supplementary S.I units.
[2]
d) Find the work done in pulling a roller through 100m horizontally when a force
of 150kg wt is acting along a chain making an angle of 600 with the ground. [2]
Question 5
a) Obtain the dimensions of the following quantities.
i)
gas constant
ii)
plank’s constant
b) Two forces, equal in magnitude have magnitude of their resultant equal to
either. Find the angle between them.
c) State the triangle’s law of vectors.
d) Explain why
i)
A man sitting in a bus gets a sudden backward jerk, if the bus starts
suddenly.
ii)
A cricket player retrace his hands backward while catching a ball.
Class XI Phy.
Page 5 of 6
MHSS. Mid-Term Exam-2010
[4]
[2]
[2]
[2]
Question 6
a) Derive an expression for kinetic energy of a body.
[4]
b) How will you measure the height of an inaccessible object?
[2]
-1
c) A cricket ball of mass 0.2kg moving with a velocity of 20ms is brought to rest
by a player in 0.1s. Find the impulse to the ball and the average force applied by
the player.
[2]


d) Draw the resultant direction of cross product of A x B in each case
[2]


B
i)
ii)
B

A
O

A
O
Question 7
a) Derive and explain the motion of the system in a horse and cart problem?
b) What is co-efficient of restitution?

c) Show that U  

mv
during the recoil of gun.
M
d) Obtain the relationship between
i)
Light year and Astronomical unit
ii)
Parsec and Light year.
Page 6 of 6
[2]
[2]
All the best.
Class XI Phy.
[4]
[2]
MHSS. Mid-Term Exam-2010