Inter (Part-I) Dera Ghazi Khan Board 2015
Physics
Part I (Objective Type)
Time Allowed: 20 Minutes 
Max. Marks: 17

Note: You have four choices 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.

Question #1

• One of the following is not a fundamental quantity

(a) Length
(b) Mass
(c) Time
(d) Wight

• Computer chips are made of

(a) Silicon
(b) Calcium
(c) Cadinium
(d) Carbon

• Which one is a scalar quantity?

(a) Power
(b) Electric field
(c) Magnetic field
(d) Average velocity

• A force of 5 N is acting along y-axis, its component along x-axis is

(a) 10 N
(b) 5 N
(c) Zero
(d) 4 N

• The motion of a body along a straight line is called

(a) Angular motion
(b) Linear motion
(c) Vibratory motion
(d) Circular motion

• The tidal energy is due to gravitational pull of

(a) Sun
(b) Moon
(c) Earth
(d) Mars

• One evolution is equal to

(a) π rad
(b) 2 π rad
(c) π/2 rad
(d) π/4 rad

• The rotational K.E of a disc is equal to

(a) ½ mv²
(b) ¼ mv²
(c) 1/6 mv²
(d) 1/8 mv²

• The pressure will be low where speed of the fluid is

(a) Constant
(b) High
(c) Low
(d) Zero

• When the soldiers cross a bridge, they are advised to march out of step due to

(a) Resonance
(b) High frequency
(c) Noise produced
(d) Fact that bridge is weak

• A spectator watching a cricket match sees the bat striking the ball and hears the sound of this about half a second later. This is because light waves and sound waves have a different

(a) Amplitude
(b) Intensity
(c) Frequency
(d) Speed

• The distance between two consecutive modes of a stationary wave is

(a) 2λ
(b) λ
(c) λ/2
(d) λ/4

• Which one of the following proves that light waves are transverse in nature?

(a) Interference
(b) Diffraction
(c) Polarization
(d) Reflection

• Huygen’s principle is used to

(a) Determine the speed of light
(b) Locate the wave front
(c) Explain polarization
(d) Find index of Refraction

• The magnification of simple microscope can be expressed as

(a) 1+f/d
(b) 1-f/d
(c) 1-d/f
(d) 1+d/f

• Pressure of a gas is directly proportional to

(a) Potential energy
(b) Kinetic energy
(c) Wind energy
(d) Sound energy

• The process in which temperature remains constant is called

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

Inter (Part-I) Dera Ghazi Khan Board 2015
Computer
Part I (Subjective)
Time Allowed: 3.10 Hours 
Max. Marks: 83

SECTION-1

2 Write short answers any Eight (8) questions of the following. 16

• Give the drawbacks to use the period of a simple pendulum as a time standard?
• Does a dimensional analysis give any information on constant of proportionality that may appear in an algebraic expression? Explain
• A light year is a distance, light travels in one year. How many meters are there in one light year. (Speed light = 3x10⁸ m/Sec)
• The vector sum of three vectors give a zero resultant, what can be the orientation of the vectors?
• Under what conditions, would a vector have compounds that are equal in magnitude?
• Can a body rotate about its centre of gravity, under the actions of its, Weight?
• What is the difference between uniform velocity and variable velocity?
• Explain the circumstances in which the velocity “V” and acceleration “a” of a car are
  • (i) Parallel (ii) Perpendicular to one another
• Define impulse and show that how it is related to linear momentum?
• A person holds a bag of groceries, while standing still, talking to a friend, A car is stationary with its engine running from the stand point of work, how are these two situations similar?
• A boy uses a catapult to throw a stone which accidentally smashes a green house window, list the possible energy changes?
• An object has one joule of energy explain what does it mean?

3 Write short answers any Eight (8) questions of the following. 16

• Show that S = rθ
• Show that orbital angular momentum L₀=mvr
• When mud flies off the tyre of a moving bicycle, in what direction does it fly?
• Define equation f continuity with mathematical form
• A person is standing near a fast moving train, Is there any danger that he will fall towards it?
• Explain what do you understand by the terms viscosity?
• What are damped oscillations?
• Can we realize an ideal simple pendulum?
• What is the total distance travelled by an object moving with SHM in a time equal to its period, if its amplitude is “A”?
• What is the effect of density on speed of sound?
• As a result of distant explosion, an observer senses a ground tremor and then hears the explosion. Explain the time difference.
• Define node and antinode.

4 Write short answers any six (6) questions of the following. 12

• How would you manage to get move orders of spectra using a diffraction grating?
• What is difference between un-polarized and plane-polarized lights?
• Define thin films
• One can buy a cheap Microscope for use by children, the images seen in such a Microscope have colored edges, why is this so?
• Write a name of three types of optical Fiber
• Differentiate between angular and linear Magnification
• Can the Mechanical Energy by converted completely into heat energy? If so give an example
• What happens to temperature of room? When an air conditioner is left running on table in middle of the room
• Give an example of Natural process that involves an increase in entropy

SECTION-II

Note: Attempt any three questions from this section 8x3=24

Question #5
(a) Describe elastic collision in one dimension. Show that Relative Velocities before collision = Relative Velocities after collision (5)
(b) Find the angle between the two vectors  = 5î + j B = 2î + 4j (3)

Question #6
(a) Show that work done in gravitational field is dependent of path followed (5)
(b) A body of moment of inertia I = 0.80 kg m² about a fixed axis, rotates with a constant angular velocity of 100 rad S^-1. Calculate its angular momentum “L” and torque to sustain this motion (3)

Question #7
(a) Define terminal velocity, also derive the relation for it when a fog droplet is moving in air (5)
(b) A heat engine performs 100 J of work and at the same time rejects 400 J heat energy to the cold reservoir. What is the efficiency of heat engine? (3)

Question #8
(a) What is resonance. Explain with three examples where resonance plays an important role (2+3)
(b) An organ pipe has a length of 50 cm. Find the frequency of its fundamental note and the next harmonic when its open at both ends. Speed of sound = 350 m/S (3)

Question #9
(a) Explain Young’s double slit experiment for interference of light and derive the expression to find the maxima and minima on the screen (5)
(b) An Astronomical Telescope having magnifying power of 5 consist of two thin lenses 24 cm apart. Find the focal length of the lenses (3)