BAHAWALPUR Board 2013
PHYSICS
Inter Part— I
Time Allowed: 3 Hours
Note:-Three are THREE sections in this paper i.e. Section A. B and C. Attempt Section-A on the same paper and return it to the superintendent within the given time. No marks will be awarded for Cutting, Erasing or Overwriting. Marks of Identification will lead to UFM case, Mobile Phone etc are not allowed in the examination hall.

• When the temperature of source and sink are equal then efficiency of Carnot's Engine is:

1.  Maximum
2.  One
3.  Zero
4.  None of these

• In an Adiabatic process:

1.  Q= Δu+w
2.  Q = Δu
3.  Q = w
4.  Q = 0

•  Spectrometer is used to study the:

1.  Spectra
2.  Interference
3.  Diffraction
4.  None of these

•  The blue colour of the sky is due to:

1.  Diffraction
2.  Reflection
3.  Polarization
4.  Scattering

•  If 30 waves per second pass through a medium at a speed of 30 m the wavelength is:

1.  30 m
2.  15 m
3.  1 m
4.  280 m

•  In standing wave if  =  (length of string) the number of loops will be:

1.  1
2.  2
3.  3
4.  4

•  If stretching force "T" of a wire Is increased then its frequency:

1.  Decreases
2.  Increases
3.  Remains the same
4.  One half

•  The length of second's pendulum is:

1.  100 cm
2.  90 cm
3.  99.2 cm
4.  98 cm

•  An object moving through fluid experience a retarding force called:

1.  Frictional Force
2.  Gravitational Force
3.  Drag Force
4.  Conservative Force

•  A body of mass 7 kg moves along a circle of radius 4 m with constant speed of 8 ms -1, the centripetal force on the body is:

1.  48 N
2.  8 N
3.  128 N
4.  112 N

•  Minimum number of communication satellites required to cover the whole earth is:

1. 4
2.  3
3.  2
4.  5

•  The time rate of change of angular velocity is called:

1.  Acceleration
2.  Angular Acceleration
3.  Impulse
4.  Inertia

•  The work done will be zero when the angle between force () and displacement ( ) is:

1. 4
2. 6
3. 9
4. 18 

•  The horizontal component of velocity of projectile:

1.  Remains Constant
2.  Increase
3.  Decrease
4.  None of these

•  The horizontal rang of projectile at 3 with horizontal is same as at an angle:

1.  4 
2.  4 
3.  6 
4.  9 

•  The resultant of two forces 30 N and 40 N acting at angle of 9 with each other is:

1. 30 N
2.  40 N
3. 50 N
4. 70N

•  The dimension of force is:

1.  MLT
2.  MLT^-1
3.  ML^-1T^-1
4.  MLT^-2

SUBJECTIVE PART

Q.2 Attempt any 8 parts.

1. Define Physics, significance figures.
2. Define Radian, Steradian.
3.  Can you add zero to a null vector?
4. Define Displacement, instantaneous velocity
5.  State Newton's first and third Law of motion.
6. Define impulse and isolated system.
7.  Write the dimension of (i) Pressure (ii) Density.
8.  Give the drawback to use the period of a pendulum as a time standard.
9.  Can the magnitude of a vector have a negative value?
10.  Can a vector have a component greater than the vector's magnitude?
11.  At what point or points in its path does a projectile have its minimum speed, its maximum speed?
12.  Why flag droplets appear to be suspended in air?

Q.3 Attempt any 8 parts.

1. Calculate the work done in kilo joules in lifting a mass of '10 kg through height of 10 m
2. When a rocket re-enters the atmosphere it's nose becomes very hot? Where this heat energy does comes from?
3.  What is meant by moment of inertia? Explain its signification.
4.  Explain the difference between Tangential velocity and angular velocity.
5.  What are Geo-stationary satellites?
6.  Name two characteristics of simple harmonic motion.
7.  Explain the terms Node an Antinode.
8.  Differentiate between free and force Oscillations.
9.  What is total distance traveled by an object moving with SHM in a time equal to its period if amplitude is A?
10.  What feature do longitudinal wave have in common with transverse waves?
11.  How astronomers use the Doppler Effect to calculate the speeds of different stars?
12.  How pollution can be reduced?

 Q.4 Attempt any 9 parts.

1. State Huygens’s principle.
2.  How the power is lost in optical fiber?
3.  Under what conditions two or more sources of light behave as Coherent Sources?
4.  An oil film spreading over a wet foot-path shows colors. How does it happen?
5.  What is meant by Linear Magnification and angular magnification?
6. Derive Charles's law from Kinetic Theory of gases.
7.  Is it possible to construct a heat engine that will not expel heat into the atmosphere?
8.  What happen to the temperature of the room when an air conditioner is left running on a table in the middle of the room?
9.  Is it possible to convert internal energy into mechanical energy? Explain with example.

                                                              SECTION-II
Q5:

1.  Define projectile motion. Drive expression for height of projectile and time of flight.
2.  The positions of two aero planes at any instant are represented by two points A (2, 3, 4) and B (5, 6, 7) in Km. Calculate the distance between the two aero planes.

Q6:

1.  Explain inter conversion of P.E and K.E. 5
2.  A disc without slipping rolls down a hill of height 10.0 m. If the disc starts from rest at the top of the hill, what is its speed at the bottom?

Q7:

1.  What is Doppler's effect? What change in frequency receiving by observer when source is moving away and towards the observer at rest? Explain.
2.  A block of mass 4 kg is dropped from a height of 0.80 m on to a spring of spring constant K = 1950 Nm^-1 Find the maximum distance through which the spring will be compressed.

Q8:

1.  What is compound Microscope? Write down its working and magnification.
2.  X-rays of wavelength 0.150 nm are observed to undergo a first order reflection at a Bragg angle of 13.3° From a quartz (Sio₂) crystal. What is the inter planer spacing of the reflecting planes in the crystal?

Q9:

1.  Explain CARNOT engine and state CARNOT's theorem.
2.  Water flows through a hose, whose internal diameter is 1 cm at a speed of 1 ms^-1? What should be the diameter of the nozzle if the water is to emerge at 21 ms^-1?