Physics
Lahore Board 2015
Inter Part-I
Group – I
Time: 20 Min.
Objective Type
Marks = 17
Note:  Four possible answer A,  B,  C  and D to each question are given the choice which you think is correct, fill that circle in front of that question with marker or pen ink in the answer-book cutting or filling two or more circles will result in zero mark in that question.

• The dimensions of work are :

(A) [MLT^-1]
(B) [MLT^-1]
(C) [ML²T^-2]
(D) [MLT]

• The speed of sound in air does not depend upon :

(A) Density
(B) Pressure
(C) Humidity
(D) Temperature

• The S.I units of angular momentum are given by :

(A) J.S^-2                           
(B) J.S^-1
(C) J.S                             
(D) J.M

• The distance between two consecutive nodes is :

(A)  λ/2
(B) λ/4
(C) λ
(D) 2 λ

• S . I unit of intensity of light is :

(A) Ampere                                 
(B) Mole
(C) Candela                                 
(D) Joule

• The S.I units of flow rate are :

(A) m²S^-1                          
(B) m³S^-2
(C) m³S^-1                          
(D) m²S^-2

• Number of spark plugs needed in the diesel engine are:

(A) 0                                
(B) 1
(C) 2                                
(D) 3

• Bending of light around the edges of an obstacle is called :

(A) Refraction                  
(B) polarization
(C) Interference                
(D) Diffraction

• The Difference between C_p and C_v is equal to:

(A) Plank’s constant         
(B) General gas constant
(C) Molar gas constant      
(D) Boltzmann constant

• The magnitude of î . (ĵ X k̂) is equal to :

(A) 0                                
(B) Pressure
(C) -1                               
(D) î

• One radian is equal to:

(A) 57.3°                         
(B) 56.3°
(C) 58.3°                         
(D) 360°

• The light emitted from light emitting diode (LED) has a wave length :

(A) 1.3μm                        
(B) 1.2μm
(C) 1.4μm                        
(D) 1.5μm

• If amplitude of a simple pendulum is increased by 4 times the time period will be :

(A) Four times                  
(B) Half
(C) Same                         
(D) Two times

• Beats can be heard when difference of frequency is not more then :

(A) 8 Hz                           
(B) 10 Hz
(C) 4 Hz                           
(D) 6 Hz

• When the body moves with constant acceleration, the velocity time graph is:

(A) Parabola                    
(B) Hyperbola
(C) Straight line
(D) Curve

• A man of mass 5 kg is falling freely, the force acting on it will be :

(A) 5 N                            
(B) 9.8 N
(C) 19.6 N                       
(D) Zero

• Motion of a projectile is :

(A) One dimensional        
(B) Two dimensional
(C) Three Dimensional
(D) Four dimensional

Physics
Lahore Board 2015
Inter Part-I 
Group – I
Time: 3.10 hrs.
Essay Type
Marks = 83

SECTION -I

2. Write short answers to any EIGHT (8) question: (16)

• What are the dimensions and unit of gravitational constant G in the formula: F = G ?
• How many seconds are there in one year?
• What are the main frontiers of fundamental science?
• Can a vector have a component greater the vector’s magnitude?
• Define the two condition of equilibrium.
• Differentiate between distance and displacement.
• Define range and time of flight of a projectile.
• Can you add zero to a null vector.
• Write down the two uses of dimensional analysis.
• Can the velocity of an object reverse the direction when acceleration is constant? Is so, give an example?
• Explain the circumstances in which the velocity ‘V’ and acceleration ‘a’ of a car are :
  (a) Parallel. (b) Anti-parallel.
• Explain the difference between laminar flow and turbulent flow.

3. Write short answers to any EIGHT (8) question : (16)

• A force ‘F’ acts through a distance "L" The force is then increased to '3F' and the acts through a further distance of ‘2L’ Draw the work diagram to scale and calculate total work done.
• When a rocket re-enters the atmosphere, its nose cone become very hot. Where dose this heat energy come from?
• Define work energy principle. Also write down its equations.
• Explain what is meant by centripetal force. Why is must be furnished to an object if it is to follow a circular path?
• When mud files off the type of a moving bicycle? In what direction does it fly?
• Show that orbital angular momentum L₀ =mvr.
• Show that in simple harmonic motion, the acceleration is zero when th velocity is greatest and the velocity is zero when the acceleration is greatest.
• What happens to the period of a simple pendulum if its length is doubled? What happens if suspended mass is doubled?
• Describe some common phenomenon in which resonance plays an important role.
• What features do longitudinal waves have in common with transverse waves?
• Explain the terms crest, trough, node and antinodes.
• Explain why sound waves travel faster in warm air then in cold air.

4. Write short answers to any six (6) questions : (12)

• How would you distinguish between unpolarized light and plane-polarized light?
• An oil film spreading over a wet footpath shows colors. Explain how does it happen?
• Why the Polaroid sunglasses are better than ordinary sunglasses?
• What are uses of spectrometer?
• Why would it be advantageous to use blue light with a compound microscope?
• Why is the average velocity of the molecules in a gas zero but the average of the square of the velocities is not zero?
• A thermo flask containing milk as a system is shaken rapidly. Does the temperature of the milk rise?
• Define absolute zero using cannot cycle.
• Is it possible to construct a heat engine that will not expel heat into the atmosphere?

SECTION-II

Note: Attempt any THREE questions.

5. (a) Define projectile motion. Derive mathematical formula for height and time of the filight. (5)

(b) Find the projection of vector A = 2 î - 8 ĵ + k in the direction of vector B = 3 î - 4 ĵ - 12k. (3)

6. (a) Explain work done in gravitational field. Also define conservative field. (5)

(b) What is the least speed at which an aeroplane can execute a vertical loop of 1.0 km radius, so that there will be no tendency for the pilot to fall down at the highest point?  (3)

7. (a) What is simple pendulum? Show that its motion is S. H. M. Derive expression for its time period. (5)

(b) A stationary wave is established in a string which is 120 cm long and fixed at both ends. The string vibrates in four segments, at a frequency of 120 Hz. Determine its wavelength and the fundamental frequency.  (3)

8. (a) Define the construction and working of Michelson’s interferometer. (5)

(b)  An astronomical telescope having magnifying power of 5 consists of two thin lenses 24 cm apart. Find the focal lengths of the lenses. (3)

9. (a) Define terminal velocity. Show that terminal velocity is directly proportional to the square of radius. (5)

(b) 336 J of energy iis required to melt 1 g of ice at 0^° C What is the change in entropy of 30 g of water At 0^° C as it is changed to ice at 0^° C by a refrigerator?  (3)

SECTION – III (Practical Part)

A . Attempt any four questions.

• Derive the formula g = to be used in free fall experiment.
• What is meant by pitch of screw gauge? Also give its least count.
• If the bob of the pendulum is replaced by another bob of different material, what will be the effect on time period?
• What is end correction?
• Find the critical angle of glass, if its refractive index is 1.52.
• What are the sources of errors during the experiment determination of focal length of convex lens by displacement method?
• Why does the paper rider fly off a fixed length of wire of sonometer?
• Design a table of observations to prove law of simple pendulum i.e. time period is independent of the amplitude.

B . Write down the brief procedure to verify that time period is directly proportional to the square root of length of simple pendulum.   (3)

OR

Write down the brief procedure to verify the law of length of stretched string by using a sonometer.

C . Answer the following question on the basis of graph below:

• Find slope of graph.
• Find length of second pendulum.         (4)

Image page no. 102

OR

• Find focal length of lens from graph.
• When 1/p = 0.05cm^-1 find value of  1/q ?

Image page no. 103

Physics
Lahore Board 2015
Inter Part-l 
Group – II
Time: 20 Min.
Objective Type
Marks = 17
Note:  Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with marker or pen ink in the answer-book cutting or filling two or more circles will result in zero mark in that question.

• Original source of energy for biomass is:

(A) Earth
(B) Moon
(C) Sun
(D) Star

• Angle between ray of light and wave front:
  (A) 0°
  (B) 60°
  (C) 90°
  (D) 120°

• The dimension of angular velocity are:

(A) [LT^-1]
(B) [LT^-2]
(C) [L^-1T]
(D) [T^-1]

• Sound travels faster in:

(A) CO₂
(B) H₂
(C) O₂ 
(D) He

• Significant fiqures in 0.0010 are:

(A) 1
(B) 2
(C) 3
(D) 4

• The dimensions of viscosity are:

(A) M²L^-1T^-2
(B) M^-1LT^-1
(C) M^-1L^-1T
(D) ML^-1T^-1

• The No. of spark plugs used in diesel engine is:

(A) 0
(B) 1
(C) 2
(D) 3

• Magnifying power of telescope is:
  (A)F_o/F_o
  (B)F_o/F_o
  (C)F_oF_o
  (D)1/F_oF_o

• Heat is from of:

(A) Power
(B) Energy
(C) Momentum
(D) Torque

• The direction of vector in space is specified by:

(A) 1-Angles
(B) 2-Angles
(C) 3-Angles
(D) 4-Angles

• The centripetal acceleration is also called:

(A) Power
(B) Radial
(C) Angular
(D) Rotational

• The distance covered by wave in 1 sec. is:

(A) Wave number
(B) Wave lenght
(C) Frequency
(D) Wave speed

• Half wavelength corresponds to:

(A) 0°
(B) 90°
(C) 180°
(D) 360°

• The distance between two consecutive nodes:

(A) π/2
(B) π/4
(C) λ
(D) 2λ

• Unit of moment in S.I. system is:

(A) N-m
(B) N-m²
(C) N²-m
(D) N-S

• 1 rev/min is equal to:

(A) π/6 rads^-1
(B) π/15 rads^-1
(C) π/20 rads^-1
(D) π/30 rads^-1

• The Dimensional unit of impulse is:

(A) MLT
(B) MLT^-1
(C) ML^-1T^-1
(D) M^-1L^-1T^-1

Physics
Lahore Board 2015
Inter Part-I 
Group – II
Time: 3.10 hrs.
Essay Type
Marks = 83

SECTION -I

2. Write short answers to any EIGHT (8) questions: (16)

• Name the several repetitive phenomenon occurring in nature which could serve as a reasonable time standard.
• Write the dimensions of:
  (a) Pressure. (b) Density.
• Why do we find it useful to have two units for the amount of substance, the kilogram and the mole?
• The period of simple pendulum is measured by a stop watch. What type of errors is possible in the time period?
• Can a body rotate about its centre of gravity under the action of its weight?
• Name the three different conditions that could makes A₁ x A₂ = O
• Can the magnitude of a vector have a negative value?
• Why a motorcycle’s safety helmet is padded?
• Show that rang of projectile is maximum when projectile is thrown at an angle of 45° with horizontal.
• Can the velocity of an object reverse the direction when acceleration is constant? If so give an example?
• Explain the circumstances when the velocity ‘V’ And acceleration ‘a’ of a car are:(a) Parallel (b)  Anti parallel
• Why foq droplets appear to be suspended in air?

3. Write short answers to any EIGHT (8) questions: (16)

• What sort of energy is in the following (a) Compressed spring (b) A moving car
• A boy uses a catapult to throw a stone which accidentally smashes a green house windo. List the possible energy changes.
• Define kilowatt hour show that 1 kwh = 3.6 x 10⁶ J.
• What is meant by moment of inertia? Explain its significance.
• Show that orbital angular momentum L₀ = mvr.
• Write down application of communication satellites.
• Name two characteristics of simple harmonic motion.
• What is the total distance travelled by an object moving with SHM in time equal to its period, if its amplitude is A?
• Show that in SHM the acceleration is zero when the velocity is greatest and velocity is zero when the acceleration is greatest.
• What is the principle of superposition?
• Explain the term crest, trough, node and antinodes.
• As a result of a distant explosion, an observer senses a ground tremor and then hears the explosion. Explain the time difference.

4. Write short answers to any SIX (6) questions: (12)

• How would you distinguish between un-polarized and plane-polarized lights?
• An oil film spreading over a wet footpath shows colours Explain how dose it happen.
• Write down two methods by which we can obtain plane-polarized beam of light from un-polarized light.
• Why would it be advantageous to use blue light with a compound microscope?
• Write down the three major components on which a fiber optic communication system consists.
• Why is the average velocity of the molecules in a gas zero but the average of the square of the velocities is not zero?
• Is it possible to construct a heat engine that will not expel heat into the atmosphere?
• State second law of thermodynamics in terms of entropy.
• Define triple point of water also write down its value.

SECTION-II

Note: Attempt any THREE questions.

5. (a) Define vector product of two vectors also write the characteristics of vector product of two Vectors. (5)

(b) A football is thrown up ward with an angle of 30° with respect to the horizontal. To throw a 40 m pass what must be the initial speed of ball? (3)

6. (a) Prove that work done by gravitational field is independent of the path followed. And what you conclude from this? (5)

(b) What should be the orbiting speed to launch a satellite in a circular orbit 900 km above the Surface of the earth? (Take mass of earth as 6 x  10²⁴ kg and its radius as 6400 km) (3)

7. (a) What is Doppler’s effect? Discuss the cases when the source moves towards and away from a Stationary observer. (5)

(b) A simple pendulum is 50 cm long, what will be its frequency of vibration at a place where the G = 9.8 ms^-2? (3)

8. (a) What is compound microscope? Derive mathematical expression for its magnification. (5)

(b)  In a double slit experiment the second order maximum occurs at Ɵ = 0.25°. The wavelength Is 650 nm determine the slit separation.   (3)

9. (a) State and prove the Bernoulli’s equation in dynamic fluid, that relates pressure to fluid speed and height.  (5)

(b) A mechanical engineer develops an engine working between 327°C and 27°C and claims to have an efficiency of 52% does he claim correctly? Explain.  (3)

SECTION – III (Practical Part)

A . Attempt any four questions.   (8)

• Find the least count of screw gauge if its pitch is 1 mm.
• Suppose we have two forces and  in which conditions their resultant will be maximum and minimum.
• What do you mean by free fall?
• Why should the bob of simple pendulum be kept very near the floor of laboratory?
• What is law of tension?
• What is the effect of density on velocity of sound?
• Define principal focus and show it by a ray diagram of a concave lens?
• What is prism?

B. Write down the brief procedure to find experimentally the area of cross section of write by using screw gauge

OR

Write down the brief procedure to verify experimentally the law of length of vibration of stretched string by Sonometer? 

C . Answer the following questions on the basis of graph drawn below:

• Calculate the value of ‘g’ from graph
• What you infer from graph?

Image page no. 108

OR

• What does the graph indicate? (4)
• Calculate frequency from graph corresponding to resonant length 15.4 cm. (2)

Image page no. 108