Multan Board 2017
Physics
PART - I
Time: 30
Group 1
Note: Write answers to the questions on the objective answer sheet provided. Four possible answers A, B, C and D to each question are given. Which answer you consider correct, fill the corresponding circle  A, B, C and D given in front of each question with Marker or pen ink on the answer sheet provided.

• Sodium Chloride in a flame gives:-

1. Green light
2. Blue light
3. White light
4. Yellow light

• If an object lies at focus point Fin front of a convex lens, its image is formed at:-

1. 2F
2. F
3. 3F
4. Infinity

• The process in which temperature of the system remains constant is:-

1. Isobaric
2. Isothermal
3. Isochoric
4. Adiabatic

• The efficiency of n Carnot Heat Engine is 100% if temperature of sink T2 is:-

1. 0°
2. 0K
3. 0°F
4. 100K

• _____is a derived unit.

1. Newton
2. Ampere
3. Candela
4. Kelvin

• If |AxB| = |A.B| then angle between the vectors A and B is:-

1. 0°
2. 90°
3. 45°
4. 180°

• A ball is dropped from rest position from a high tower. The distance covered by it in 2 seconds during freely falling is:-

1. 9.8 m
2. 4.9m
3. 19.6m
4. 39.2m

• The maximum horizontal range of a projectile is given by:-

1. Vi²/g
2. Vi²/2g
3. 2Vi/g
4. 2Vi²/g

• Watt — m^-2 is the unit of

1. Energy
2. Intensity
3. Power
4. Work

• The angular speed of a flywheel making 120 revolution per minute is,

1. 2π rad
2. 120 rad s^-1
3. k red s^-1
4. 4π rad s^-1

• When a body moves in a circle, the angle between linear velocity and angular velocity is:-

1. 0°
2. 90°
3. 45°
4. 180°

• The ratio of rotational K.E. of a hoop to its translational K.E. is:-

1. 1 : 2
2. 2 : 1
3. 1:1
4. 1 : 4

• A 2 meter high tank is full of water. If a hole appears at its middle, then the speed of efflux is:

1. 4.4ms^-1
2.  10ms^-1
3. 6.2ms^-1
4. 20 ms^-1

• A spring has a spring constant K. If it is cut in two equal parts, the spring constant of each part will he:-

1. K
2. 2K
3. K/2
4. 4K

• The speed of stars and galaxies can be calculated by:-

1. Compton Effect
2. Stefan's Law
3. Doppler's Effect
4. Pascal's Law

• A string of length of fixed at both ends is vibrating in two segments, the wavelength of wave is:-

1. L/2
2. L
3. 2L
4. 3L

• Stationary waves are generated on a string of length L. If tension is increased, frequency of vibration will:-

1. Decrease
2. Unchained
3. Half
4. Increase

SUBJECTIVE PART
   SECTION B

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

1. How you can find uncertainty in a timing experiment'?
2. Check the correctness of relations v = r ω
3. The period of simple pendulum is measured by a stop watch
4. What type of errors are possible in the time period?
5. Why do we find it useful to have two units for the amount of substance the kilogram and the mole?
6. Define position vector and explain it briefly.
7. Is it possible to add a vector quantity to a scalar quantity? Explain.
8. Name three different conditions that could make 2 = 0
9. Which will be more effective in knocking a bear down? (a) A rubber bullet or a lead bullet of same momentum. Why?
10. What is a Ballistic Missile and Ballistic Trajectory?
11. Explain the circumstance in which the velocity v and acceleration of a car are (a) parallel (b) perpendicular to one another
12. A man wishes to take a long jump. At what angle he should jump? Explain.

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

1. Calculate the work done in Kilo Joules in lifting a mass of 10 kg (at a steady velocity) through a vertical height of 10m.
2. Define escape velocity and write only the formula of escape velocity.
3. A boy drops a glass from a certain height which breaks into pieces.
4. What energy changes are involved?
5. What is meant by Angular Momentum? State only law of Conservation of Angular Momentum
6. Why does a diver change his holly positions before and after diving in the pool?
7. What is the difference between Real and Apparent weight?
8. What happens to the period or simple pendulum if its length is doubled?
9. Describe some common phenomena in which resonance plays an important role.
10. Define free end Forced Oscillations.
11. Explain the term Crest and Node.
12. Explain why sound travels faster in warm air than cold air.

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

1. What is a Diffraction Grating and Grating Element?
2. What is Optical Rotation or Optical Activity'?
3. How would you distinguish between 'un-polarized and plane-polarized light?
4. What is Optical Resolution and Resolving Power'?
5. Draw the ray diagram of astronomical telescope when it is in normal adjustment.
6. Why spark plug is not needed in a diesel engine'?
7. Specific heat of a gas at constant pressure is greater than that at constant volume. Why?
8. Write down two statements of 2nd Law of Thermodynamics.
9. What is an Adiabatic Process? Draw a graph between pressure and volume of an adiabatic process and give name of this graph.

SECTION-C

Note: Attempt any THREE questions.
Q 5.

1. Describe Vector Addition by using their rectangular components. Derive the relation for the magnitude and direction of the resultant in case of two vectors and n-vectors.
2. A 100 g golf ball is moving to die right with a velocity 20ms^-1. It snakes a head on collision with an 8 kg steel, ball initially at rest. Find the velocities of balls after collision.

Q 6.

1. What is a Geostationary Satellite? Derive an expression for Orbital Radius of the path of Geostationary Satellite.
2. 100 m3 of water is pumped from a reservoir into a tank, 10m higher than the reservoir, in twenty minutes. Find the power delivered by the pump if density of water if 1000 Kgm^-3

Q 7.

1. Define molar specific heat at constant Volume and. Molar specific heat at constant pressure. Prove that C_p— C_v = R
2. Water flows through a hose, whose internal diameter is 1cm 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?

Q 8.

1. Describe the transverse stationary waves in a stretched string. Show that the frequencies of stretched string are quantized.
2. A simple pendulum is 50 cm long. What will be its frequency of vibration at a place where g = 9.8 ms^-2

Q 9.

1. What is Astronomical Telescope? Derive relation for its Magnifying Power.
2. In a double slit experiment, the second order maximum occurs at θ = 0.25°. The wavelength is 650 nm. Determine the slit separation.