RAWALPINDI BOARD 2016
PAPER PHYSICS
PART-I
Time: 20 Min.
(Objective Part)
Marks: 17
Note: You have four choice for each objective type question as A, B, C and D. The choice which you think is correct; fill that circle in front of that question number. Use marker or pen to fill the circles. Cutting or filling two or more circles will result in zero mark in that question.

• Fring spacing is equal to:

(a)
(b)
(c)
(d)

• In multimode step index fibre, the diameter of core is:

(a) 5μm
(b) 50μm
(c) 100μm
(d) 150μm

• Efficiency of steam locomotive is:

(a) 10%
(b) 9%
(c) 8%
(d) 7%

• Cloud formation in atmosphere is an example of:

(a) Isothermal process
(b) Adiabatic process
(c) Isobaric process
(d) Isochoric process

• One pico is equal to:

(a) 10¹²
(b) 10^-12
(c) 10^-6
(d) 10⁶

• Dot product of a vector with itself is:

(a) Zero
(b) 2A
(c) A²
(d) A

• Unit of acceleration is:

(a) ms^-1
(b) ms
(c) ms^-2
(d) m²s

• The overcome gravity, fuel consumed by rocket is:

(a) 40000kgs^-1
(b) 30000kgs^-1
(c) 20000kgs^-1
(d) 10000kgs^-1

• 1 kilowatt hour is a unit of:

(a) Energy
(b) Power
(c) Pressure
(d) Force

• The mass of earth is equal to:

(a) 6 x10²⁴kg
(b) 5 x10²⁴ kg
(c) 6 x 10²⁰ kg
(d) 5 x10²⁰ kg

• The height of the geostationary satellite above the equator is:

(a) 35000Km
(b) 36000Km
(c) 34000Km
(d) 33000Km

• Dimension of angular velocity is:

(a) [LT^-1]
(b) [LT]
(c) [L²T]
(d) [T^-1]

• The law of conservation of mass gives:

(a) Bermoulli's equation
(b) Venturi relation
(c) Torricelli's theorem
(d) Equation of continuity

• Frequency and time period are related as:

(a) ƒ T^-1=1
(b) ƒ T =1
(c) ƒ T^-1 =1
(d) ƒ T^-2=1

• Stars moving towards the earth show:

(a) Red shift
(b) Blue shift
(c) Yellow shift
(d) Green shift

• Speed of sound in copper is:

(a) 38000ms^-1
(b) 3600ms^-1
(c) 3500ms^-1
(d) 3400ms^-1

• Velocity of sound is independent of:

(a) Temperature
(b) Density
(c) Pressure
(d) Medium

Time: 2:40 Hours
(Subjective Part)
Marks: 68
Section I

2. Attempt any EIGHT short questions.

• Write the demension of pressure and density.
  
• Define random and systematic error.
  
• The period of simple pendulum is measured by stop watch. What type of errors are possible in the time period?
  
• Define and explain significant figures.
  
• Is it possible to add a vector quantity to a scalar quantity? Explain.
  
• Name three different conditions that could make  = 0.
  
• What do you understand by positive and negative torques?
  
• Can velocity of an object reverse the direction, when acceleration is constant, if so, give an example. (ix) Defien impulse and show that how is it related to linear momentum?
  
• Why is the first law of motion also called law of inertia?
  
• What is ballistic missile? Define its trajectory.
  
• Explain the difference between laminar flow and turbulent flow.

3. Attempt any EIGHT short questions. (8 X 2 =16)

• An object has 1 joule RE., what does it mean? Explain briefly.
  
• Define angular displacement and its unit.
  
• What are beats draw the diagram to show beats.
  
• Give two applications of Doppler's effect.
  
• A disc and a hoop start moving down from the top of an inclined plane at the same time, which one will be moving faster on reaching at bottom?
  
• What is the difference between free and forced oscillations? Give examples.
  
• Why does a diver changes his body position before and after diving in the pool?
  
• Write down the common features of longitudinal and transverse waves.
  
• In which case more work is done when a 50kg bag is lifted up by 50cm and when a 50kg crate is pushed through 2m by 50N force.
  
• Does the acceleration of a simple harmonic oscillator remain constant during oscillation? Discuss briefly.
  
• A person holds a bag of groceries while standing still, a car is stationary with its engine runing at stand point, how the two situations are similar.
  
• Describe some phenomenon in which resonance plays an important role.

4. Attempt any SIX short questions. (6 X 2 = 12)

• Can visble light produce interference fringes? Explain.
  
• Define thin flim. Write its two examples.
  
• How would you manage to get more orders of spectra using diffraction grating?
  
• Why would it be advantageous to use blue light with a compound microscope?
  
• If a person was looking through a telescope at the full moon. How would the appearance of the moon be changed by covering half of the objective lens?
  
• Define entropy and give its units.
  
• Why does the pressure of a gas in a car type increase when it is driven through some distance?
  
• Does entropy of a system increase or decrease due to friction? Explain.
  
• Is it possible to construct a heat engine that will not expel heat into the atmosphere? Explain.

SECTION-II

Attempt any TIIREE questions. . (8 x 3 = 24)

5. State and explain two conditions of equilibrium. A truck weighing 2500kg and moving with a velocity of 21mS-1 collides with stationary car weighing 1000kg. The truck and the car move together after the impact. Calculate their common velocity.

6. (a) Define absolute potential energy. Derive expression for it.
(b) What should be the orbiting speed to launch a satellite in a circular orbit 900km above the surface of the earth? (Take mass of the earth as 6.0x 1024kg k and its radius as 6400km).

7. (a) What is terminal velocity? Show that terminal velocity is directly proportional to the square of the radius of spherical body falling in a viscous medium.
(b) Find the average speed of oxygen molecules in air at S.T.P.

8. (a) What is simple microscope? Calculate its magnification.
(b) Sodum light (=589nm) is incident normally on a grating having 3000 lines/cm. What is highest order of the spectrum obtained with this grating?

9. (a) Explain Young's double slit experiment for interference phenomenon. Derive equations for maxima, minima and linear distance on the screen between adjacent bright fringes.
(b) A glass light pipe in air will totally internally reflect a light ray, if its angle of incidence is at least 39°. What is the minimum angle for total internal reflection if pipe is in water? (Refractive index of water = 1.33)